Hoop Barns for Grow-Finish · PDF fileHoop Barns for Grow-Finish Swine MWPS ... barns or...

Authors:

Michael C. Brumm

Extension Swine Specialist, NEREC, University of Nebraska

Jay D. Harmon

Professor, Agricultural and Biosystems Engineering, Iowa State University

Mark S. Honeyman

Professor, Animal Science, Iowa State University

James B. Kliebenstein

Professor, Agricultural Economics, Iowa State University

Steven M. Lonergan

Associate Professor, Animal Science, Iowa State University

Rebecca Morrison

Formerly of U of Minnesota, West Central Research and Outreach Center, Morris, MN

Tom Richard

Associate Professor, Agricultural and Biosystems Engineering, Penn State University

Hoop Barns for Grow-Finish Swine

MW P S

Agricultural Engineers Digest A E D 4 1 909

09/2004 / Reprint 08/2007 Published by: MidWest Plan Service. Revised Edition

Swine producers in the United States who are looking for lower coststructures in which to raise pigs have increasingly turned to so-called hoopbarns or hooped shelters as facilities in which to house grow-finish swine.Hoop barns have been rapidly adopted. For example, by 2001, Iowa farmershad erected more than 2,100 hoop barns for finishing pigs. Hoop barns can beused successfully to finish pigs, but producers need to be aware of theadvantages and disadvantages of this type of housing.

To help producers and designers resolve some of the issues involved inusing a hoop barn, this publication summarizes information about designingand using hoop barns. It discusses some of the management techniques thathoop barns require, and it presents economic factors that can be used to analyzedesign layouts and construction alternatives. The publication contains a samplebudget comparing the costs of hoop barns to the costs of more traditionalconfinement housing.

Contents

Overview 2

Basic Questions 2

When to Consider Hoop Barns 2

Designing and ErectingHoop Barns 4

Using engineered ornon-engineered hoop barns 4

Design and construction details 5Foundations 7Frames 7Covers 8Snow and wind loading 8

Environment and Ventilation 8Ventilation openings 9Endwall ventilation 9Cooling 10

Feeders and Waterers 10

Animal Management 11

Pig Performance 11Growth 11Meat quality 12Health 12

Animal Handling 12

Bedding 14

Manure Handling 16Composting manure 17Manure characteristics 17

Comparisons 18Labor requirements 18Cost analysis 19Financial analysis 21Other considerations 21Wean-to-finish 22

Summary 23

References and Resources 23

Reviewers 24

2

OverviewA hoop barn is a Quonset™-shaped structure

with sidewalls 4 to 6 feet high made of treated woodposts and wood sides or concrete. Tubular steelarches fastened to the tops or sides of the posts forma hooped roof, which is covered with UV-resistant,polyvinyl tarp. When used as swine housing, hoopbarns have concrete or earthen floors. Buildings withearthen floors have a concrete slab for a feeding andwatering area. The floor, except for the feeding andwatering area, is deep bedded and cleaned after eachgroup of pigs is marketed.

Figure 1 shows a typical installation of a hoopbarn. Figure 2 shows the common components ofhoop barns.

Hoop barns are naturally ventilated and aresited to take advantage of prevailing winds. In theMidwest, most buildings are oriented in a north-south direction.

Basic QuestionsMost of the previously available information

about using hoop barns for swine housing camefrom farmer experiences and comparisons inmagazines and news articles. Recent researchperformed in Canada and at Iowa State Universityhas added to what is known about using hoop barnsfor swine housing. Producers thinking aboutbuilding any type of swine housing need to answerquestions like the following to determine if buildingthe hoop barn is right for their situation.

1. Does the building’s design make the use ofoptimal or preferred management practicespossible and convenient?

2. Is the design conducive to providing for theanimals’ needs during all seasons?

3. Is the design structurally sound and does itmeet common tests of reliability, longevity,and insurability?

4. Is the design cost effective?5. How will the structure fit in with my overall

production goals?6. Do I have the necessary site and equipment

to operate the building?7. Are environmental permits necessary?

When to Consider Hoop BarnsHoop barns appear to be most beneficial for

producers who have one or more of the followingneeds:

• Want facilities to match a rapidly changingswine industry.

• Need a short-term structure that can beremoved after use or that can be adapted forother uses.

• Want to keep fixed costs low.• Have limited capital.• Need facilities for groups of 150 to 200+

pigs, which could be impractical for otherhousing types.

• Are not interested in accepting the financialrisk associated with a large capitalinvestment.

• Prefer to handle solid manure and have thecapability to do so.

• Have the equipment and land resources toharvest crop residue for bedding.

• Prefer a system of production that is lessautomated and requires different husbandryskills than those needed in confinementbuildings.

• Believe pigs should be reared in anenvironment with bedding.

• Need a structure built quickly.• May want to qualify for some niche

market requirements and premiumprices.

Along with the benefits, hoop barns have somedisadvantages:

• Observing animals in large groups is moredifficult.

• Hoop-housed pigs may use feed lessefficiently during cold periods.

• During inclement weather, the laborenvironment is less favorable in hoops thanin confinement buildings.

• Hoop-raised pigs may be slightly less leanthan confinement-raised pigs.

• More labor may be needed for hoops than forconfinement buildings.

• Hoops require large amounts of bedding,and labor needs for harvesting bedding mayconflict with the labor needs for harvestinggrain.

• Raccoons and other animals that can fosterfarm-to-farm disease transmission may usethe bedding storage area for nests.

• Excluding birds and other pests that maycarry diseases is difficult.

An example of a producer who should considerusing hoop barns is a farrow-finish producer with amoderate size sow herd who weans 150 or more pigs

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at one time and who currently uses a variety of outsidelots for grow-finish. Problems with pig comfort andperformance in cold weather coupled withenvironmental concerns about current manure storageand runoff control systems might lead this producerto consider a hoop barn as a housing alternative.

If the producer is seeking a facility that hasother options for use if the swine enterprise isdiscontinued, investing in hoop barns becomesmore reasonable. If this producer’s goals in porkproduction include the use of a production systemthat requires a lower capital investment or asystem that requires bedding use to qualify for aniche market, the case for using hoops becomesstronger. Finally, if equipment for harvesting cropresidue and for handling solid manure is already

Figure 1. Typical

hoop barns on a

Midwestern farm.

Note the wood sidewall,the gates, and the waythe endwall is attachedto the front posts.

Treated boards

Hoop frame

Polyvinyl tarp

Treated tongue and groove 2 lumber"

Treated posts

Ratchet tie-downs(See figure 10 for detail)

Figure 2. Common components of hoop barns.

available, the logic of investing in a hoop barn iseven more compelling.

From another perspective, many large producersare considering building one or more hoop barns as away of dealing with fluctuations in pig flow numbers.These producers consider a lower-cost building forexcess pigs to be beneficial so more expensive facilitiesalways can be stocked at an economic optimum.

Table 1 shows a comparison of various swinefinishing facilities. Hoop barns are a good alternativefor producers who are unwilling or unable to investin confinement facilities but want to move pigs fromoutside lots or Cargill-type floor units to a facilitythat has a more manageable thermal environment,that provides better runoff control, and that allowsbetter feed usage.

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Designing and Erecting Hoop BarnsProducers who decide to build a hoop barn need

to treat the construction project as they would anyconstruction project involving a new structure.Aspects to consider include what type of structure tobuild; site selection; and proper access to the buildingfor moving feed, bedding, and pigs. Producersthinking about building a hoop barn also shouldconsider the building’s usefulness within an existingoperation, its proximity to neighbors, the availabilityof services and utilities, and the possibility of usingthe structure in conjunction with existing buildings.

Using engineered or non-engineered hoop barns

Although hoop barns do not have an extensivehistory in the United States, Canadian farms havebeen using hoops for several years. In both the U.S.and Canada, many models have proven to last 10years or more if they are well maintained. Factorsinfluencing the life include the use of strong, tear-resistant tarps, corrosion resistant structuralmembers, and sidewalls that are well maintainedand not abused.

One factor producers should consider is whetherto purchase an engineered or a non-engineeredstructure. When a hoop barn is engineered, aqualified designer (typically a registered engineer)has analyzed how each component of the structurewill interact with the other components of thestructure. A qualified designer has analyzed howthe loads applied to the roof (or tarp) will affect thedesign of the tubular frame and how the tubularframe will transfer forces vertically and horizontallyto the sidewall frame.

In addition, the designer has considered theforces the animals themselves will exert against thesidewalls and has designed the sidewalls towithstand the outward push of the frame and pigs.In an engineered building, the foundation has beenspecified to withstand the loads transferred fromthe wall. Structures that are engineered have been

designed to meet snow and wind loads for thegeographic area in which they are to be erected. Animportant point for producers to consider is thatengineered structures are more easily insuredbecause they are assured to meet weather designconditions. Insurance agents should be consultedabout insurability issues before any building ispurchased and constructed.

An engineered structure typically will include theframe, tarp, sidewall materials, and materials toanchor the building to the foundation. Warranties forengineered structures range from 10 to 15 years onmaterials and workmanship. Engineered structuresoften are more insurable than non-engineeredstructures, and engineered structures often cost lessto insure.

Some hoop barns on the market have not beenengineered. Hoop barn dealers often sell a roofingsystem instead of a complete structure. Included inmost packages are the tubular frame, tarp, andmaterial to attach the tarp to the sidewalls. The buyermust purchase the wood posts and tongue and grooveboards to construct the sidewalls. Many times, non-engineered structures will have less than a three-year warranty on products and workmanship. Non-engineered structures may have little if any resalevalue after five years.

Producers must ask themselves questions likethe following when considering the purchase of ahoop barn:

• How long do I want the structureto last?

• Do I want to have the opportunity to resellthe structure in the future?

• Will the extra cost of buying anengineered structure outweigh the savingsof buying a less expensive, non-engineeredstructure?

• How does having an engineered structureaffect my ability to get insurance on thestructure?

Finishing Thermal Comfort Runoff Feed Housing Pig

System Control Control Utilization Investment Management

Dirt Lots Very Poor Very Difficult Poor Very Low Very DifficultCargill Floor Unit Poor Difficult Medium Medium DifficultHoop Good Easy Good Medium Moderately EasyConfinement Very Good Easy Very Good High Easy

Table 1. Comparison of finishing systems.

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Design and construction details

Hoop barns are naturally ventilated and aresited to take advantage of the summer prevailingwinds. For much of the Midwest, the building isoriented in a north-south direction to take advantageof the summer prevailing winds from the south.Prevailing summer winds should blow into the endof the building at which the feeders and waters arelocated and should blow out the end at which thebedding is located.

In a grow-finish hoop barn, an area approximatelyone-quarter to one-third the length of the structure isprovided for feeders and waterers. The feeding andwatering slab should be planned to allow the animalsto move about the slab without disturbing animals thatare eating. For instance, circular feeders should haveat least 5 feet of open space completely around themto account for the space pigs require while eating.

In a north-south oriented structure, this slab areashould be located at the south end and extend theentire width of the structure. In such a location, thefeeding pad is sloped 1 to 2% (1/8 to 1/4 inch drop perfoot of length) to the south, or away from the beddedarea. The remaining deep-bedded area of thestructure can have either an earthen or concrete floor,with many producers preferring concrete for ease ofcleanout. A complete concrete floor will make cleaningmuch easier because it prevents the problem of pigsdigging into the underlying soil. A concrete floor alsotends to reduce bedding usage in summer becausepigs cannot dig to reach cooler soil. In some states,regulations require concrete floors to prevent

nutrients from leaching into the underlying soil andgroundwater.

If the bedding area is to be concreted, the soilshould be compacted to prevent differential settling.A five-inch slab with woven wire, placed in the center(vertically) of the slab should be sufficient for mostapplications. The concrete floor should have astrength of 4,000 psi. Thicken the edges of the slab,particularly at the end where vehicles will drive intothe bedding area for cleaning. Place the concrete flat.

When building multiple hoop barns, provide atleast 10 feet of space between buildings. This willallow space for equipment to travel betweenbuildings and allow for snow removal and moisturedrainage.

A typical hoop barn is 30 by 72 feet and holdsapproximately 195 head of finishing pigs in one largegroup. Table 2 shows the typical space distributionin a hoop barn used for housing grow-finish pigs.Optimum stocking density usually is about 11 squarefeet per pig. Figure 3 shows a common layout for agrow-finish hoop barn.

Table 2. Space distribution in a hoop barn used for

grow-finish housing.

Optimum Range

Bedded Area, sq ft per pig 8 5.8–12.7Concrete Area, sq ft per pig 3 2.3–4.2Total Area, sq ft per pig 11 10.0–15.0

Feeder Space, Pigs per space 10 5–10Drinking Spaces, Total 4 4–6

Figure 3. Typical layout for a grow-finish hoop barn.

18 - 24’72'

30' Concrete or earthen floor

for the bedded area

Waterer

Feeders

Swing gate

Swing gate

Concrete

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Wood sidewalls and concrete are both relativelycommon, with increasing interest in using concrete.For wood sidewalls, the steel frames are fastened tothe tops or sides of the posts that support the outsidewall. Commonly, pressure treated 6 x 6’s are usedas posts. Pressure treated tongue and groove 2 x 6’sare used on the animal side of the posts to form thesidewalls of the animal space.

Either poured or precast concrete walls can beused for hoop barns. Either must be designed tosupport the design loads caused by the hoops.Properly engineered hoop frames connected to precastconcrete walls, similar to those used in bunker silos,can be a good choice in that the structures can bemoved if necessary. Concrete for the sidewalls is moredurable than wood but may be more expensive, andmay be colder for the animals to lie against. Pouringconcrete sidewalls would make the hoop barn a morepermanent structure. If concrete sidewalls are used,they must be designed to accommodate the fasteningrequirements of the selected brand of hoop barn.

Typically the sidewalls are 4 to 6 feet high. Six-foot sidewalls are recommended to prevent pigs fromdamaging the tarp when a great deal of bedding hasaccumulated. Figure 4 shows the inside details of atypical hoop barn.

Livestock panels or gates form the north andsouth endwalls at animal level. In the winter, thesegates are covered with sheets of galvanized steel,recycled plastic, or plywood to reduce drafts. In allinstances, the north wall can be closed relativelytightly to reduce winter winds using commerciallyavailable tarps or plywood sheeting. Some producersalso partially close the south end in cold weather

using commercially available tarp kits, especiallyin northern climates of the United States. In thesummer, both the north and south ends are totallyopen, with the steel, plastic, or plywood panelsremoved from the end gating to increase air flow inthe pig zone.

Endwall construction should include posts thatwill be close enough to fasten the end gates adequately,but far enough apart to allow room for feeding andmanure handling equipment. If the posts extend tothe height of the hoops, do not fasten the posts to theend hoop. Hoops can deform during winds and willrub against the posts. Rubbing against the posts maydamage the tarp material. Commercially available endtarps will reduce the potential for damage. Figures 5,6, and 7 show typical endwall configurations for variousweather conditions.

Figure 4. Inside view of a typical hoop barn.

Plywood has been added above the structural wall toprevent the pigs from damaging the tarp and to directcold incoming air upwards.

Figure 6. End closed during cold weather.

This is a typical configuration for the north end ofa hoop structure in the Midwest during harsh winterweather.

Figure 5. End open during mild weather.

In the Midwest, both ends would most likely be open inmild weather. The prevailing summer wind should enter thestructure through the feeding end.

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Foundations

The foundations of hoop frames must be able totransfer the loads applied to the frame to the earth.Wind applies horizontal and uplift loads to thesidewall frame, while snow, rain, and the weight ofthe frame apply vertical loads downward to thesidewalls. The foundation anchors the barn to theearth and must resist corrosion from contact withmanure, moisture, and the soil.

The most common method of anchoring the frameto the foundation is to build a post frame wall withthe posts extended below the frost level and thenconstruct a 4- to 6-foot high wall along the sides ofthe frame. The pipe frame is attached to the tops orsides of the posts. Figure 8 shows the constructiondetails of the frame and walls. Posts must be setproperly. If posts are set improperly, they can moveout of plumb and affect the structural integrity of

the building. Posts should be set below the frost lineand on top of concrete footings. The soil around theposts must be tamped properly. Do not set posts inareas that have a high water table. Precast concretesidewalls can be placed on a crushed rock layer or onconcrete. The weight must be adequate for the hoopbarn to resist wind uplift forces. Follow engineereddesigns from the hoop barn supplier.

Frames

Hoop frames are constructed primarily from2- to 3-inch O.D. (Outside Diameter) round tubularsteel to form a roof truss system. Steel purlins connectthe trusses to each other to act as a unit. (See Figure9.) The thickness of the tubing used in frames rangesfrom 16 to 12 gauge. (The lower the gauge number,the thicker the tubing.) Frame sizes depend onbuilding width and frame spacing. Some narrowerhoops use tubing only, without forming a truss.

Frames are spaced from 6 to 16 feet apart. Theseframes support the roof and sidewall construction of thebuilding. See Figure 10 for an illustration of how thetarp is fastened to the sidewall and frame. Galvanizedsteel tubing 1-3/8 inch O.D. is used for purlins and bracingto span and brace between the frames along the lengthof the barn. Frame widths for single span structuresusually range from 18 to 36 feet.

Some manufacturers span from 40 feet to wellover 100 feet with engineered truss arches such asthe one shown in Figure 9. Truss arches also areused when high snow or wind loads are a concern,or if a lower roof height is desired.

Because of the corrosive nature of an animalhousing environment, high quality galvanizing is

Figure 9. An engineered truss arch used to support a

wider span and when snow or wind loads are a

concern.

Figure 8. Hoop barn with a standard tubular frame

under construction on an Iowa farm.

Note the wall’s framing and how the hoops attach to thetop of the posts.

Figure 7. End partially open during mild

winter weather.

During harsh winter weather, this end wouldbe fully closed.

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crucial. Some manufacturers use hot dippedgalvanizing, which produces excellent results. Othertypes of galvanizing, however, may not be suitablefor use in animal environments. Check the qualityand amount of galvanizing in the frame tubing anddetermine what type of warranty is available fromthe supplier. Aluminum frames are an option withsome suppliers. Aluminum frames used with theappropriate fasteners should experience lesscorrosion than steel in the conditions that exist intypical swine housing.

Covers

Tarp coverings for hoop barns come with vari-ous options, but evaluating what type of tarp to getshould be an integral part of the overall design anddecision-making process. Generally, tarps are madeof woven polyethylene fabric that is produced fromlow-density polyethylene extruded over high-den-sity woven polyethylene. Due to the woven natureof the tarps, punctures do not tend to run. Whenpunctures occur, they may be patched with a kit thecompany provides. The better tarps are those thathave been treated with Ultra-Violet (UV) stabiliz-ers and a fire resistant substance to provide safetyand longevity. Producers should consult their insur-ance company on which treatments are required forinsurability.

Tarps generally come in different weights, whichmay include 10.0-, 12.5-, and 14.9-ounce fabric.Many colors are available, including clear andopaque fabric. Fabrics that have a white undersideor are white and allow some light through tend tomake a barn brighter and make the animals easierto see. Clear fabrics are not a good choice becausethey allow a high degree of solar penetration, whichmay overheat animals. Pro-rated warranties fortarps are generally 10 to 15 years. Rub points, suchas purlin connections and end wall connections, tendto wear first. It is best to minimize such rub points.

Snow and wind loading

In general, the structure must be able to meetsnow and wind load requirements. Structures thatdo not meet snow and wind load requirements riskfailure and may not be insurable.

The snow load design should be similar to whatother agricultural building loads are for the area inwhich the building is being constructed. The effectof snow on the structure can vary. Snow may slideoff the roof, or the snow may accumulate and putadditional weight on the tarp and hoops. Generally,

snow loads are not seen as a big concern becausethe curvature of the structure minimizes snowbuildup.

Wind loads also should be calculated as theywould be for other agricultural structures in thearea. Additionally, uplift of the frame under windloads needs to be considered in the design of theframe and the foundation anchoring. In some de-signs, diagonal bracing of the sidewalls from theendwalls and along the roof line should be incorpo-rated. Outside guy wires can be important to keepthe frame from racking or deforming out of plumb.Frames that have shifted off center are likely to beloaded unevenly and are subject to failure. Somereports of wind damage have indicated that hoopssometimes deform without failing.

Environment and VentilationPerhaps the top priorities for hoop barns used as

swine housing are the issue of animal environmentand the related issue of proper ventilation. Realisticexpectations for these structures are that they reduceexposure to wind and snow in winter and sun andrain in summer. Hoop barns are cold structures andshould be managed as such. Although the bedded-manure pack generates considerable heat andenhances animal comfort for grow-finish pigs in thewinter, hoops require special design and managementfor year-round farrowing or nursery operations.

The primary goal of hoop barns is to protect theanimals from the weather. In the summer, the build-ing should provide shade and allow cross ventila-tion by wind pressure. In the winter, the housingshould allow for moisture removal and draft con-trol. In the winter, a cold barn with dry beddingallows the pigs to create a suitable, comfortablemicroenvironment in the bedding.

A natural tendency of producers using hoop barnsis to restrict ventilation to keep warmed air insidethe structure. However, when the hoop barn is beingused to house animals, restricting ventilation trapsthe moisture the animals produce along with thewarm air. This creates a situation that can be dam-aging to the pigs’ health.

At night a hoop barn loses heat to the coldsurroundings and the cold, clear, black sky. Thiscools the air in the structure, lowering its moisture-holding capacity substantially and causing relativehumidity to rise. The result is cold, damp air and,most likely, excessive condensation on the undersideof the tarp. If ventilation is inadequate, animals willbe subjected to wide day-to-night variations in air

9

temperature and humidity, which could adverselyaffect animal health.

To reduce risks to animal health from poor airquality, hoop barns must be well ventilated, and theventilation must be well managed. A hoop barn mustbe managed just as any cold, naturally ventilatedstructure. Do not close the structure too tightly. Donot attempt to manage the structure as a warm barn;it is primarily a shelter. Properly managed, airtemperature in the hoop barn 4- to 6-feet above thebedding pack is often within 10F of the outside airtemperature.

Because wind is a major force in ventilating anynaturally ventilated structure, orient hoop barns tointercept the prevailing summer wind through thefeeder-end opening. Do not construct hoop barnswhere buildings, trees, or other large obstructionsblock the prevailing summer winds. For moststructures, the minimum separation distance fromobstructions to the end of the barn is 75 feet.

Ventilation openings

Natural ventilation uses openings at differentheights to achieve ventilation in the winter. Buildinga structure with an open ridge will allow the moistair that builds up to escape through the opening atthe top of the structure. Ideally, a ridge opening wouldbe provided. However, many hoop barns used forswine housing do not have ridge openings. In thesebuildings, ventilation air enters through a continuousspace along the sidewall where the tarp is attachedand exits through the ends of the hoop, dependingon wind direction. Figure 10 shows a 3- to 6-inch gapbetween the top of the wall and where the tarpoverlays the wall; this gap serves as a continuous airopening for ventilation.

Because openings are not adjusted, the hoop actsmostly as a wind and snow shelter and does notmaintain a set temperature. Problems with airquality occur most often when hoop barns are closedtoo tightly.

Endwall ventilation

Hoop barns without ridge vents are difficult toventilate naturally if they are too long. Typically, ahoop barn longer than 75 feet, without ridge vents,and filled with animals will present ventilationproblems. Hoop barns up to 100 feet long can beused in high wind areas. In all areas, hoop barnsrely on endwall openings to aid airflow through thestructure. The ends are open most of the year. Figure11 shows an example of how the gap between the

top of the endwall and the frame and tarp acts toaid natural ventilation when the ends are closed.

Where such devices as hovers or wind baffleson gating are used to reduce drafts, the draftprevention devices must still allow ventilation andmoisture removal to occur.

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Figure 10. Tarp properly fastened to frame

and sidewall.

Note the space between the wall and the tarp; this spaceacts as a continuous air inlet for ventilation.

Figure 11. Hoop closed for winter.

A gap at the top serves as a continuous air openingfor ventilation.

10

Cooling

In hoop housing, as in most swine housingsystems, heat stress can be an issue for pigs, especiallyas they near market weight. Use of a sprinklingsystem will help maintain feed intake and growthrates during hot periods.

In confinement facilities with liquid manuresystems, cooling can be accomplished using athermostat and cycle timer with a sprinkler systemto wet the pigs and then allow them to dry. Allowingthe water to evaporate between cycles draws heatfrom the pigs’ bodies as the water evaporates offtheir skin. This evaporation helps to cool the pigs.Any excess water ends up in the manure collectionsystem.

With hoop barns, a similar system can work, butthere are a few obstacles. Hoop barns are not alwaysequipped with electricity so the use of a thermostatand cycle timer may not be practical. Excess waterwill go into the bedding rather than into a manurecollection system thereby causing a wet place forthe pigs to lie, even when temperatures cool off inthe evening.

Work in Australia with bedded finishing systemshas shown that it is best to wet most of the pigs atthe same time. This spreads the water across a largearea, including the bedded area, and helps to avoidexcessive water on the bedding. Sprinklers can beattached to the roof trusses to cover a portion of thebarn. With this type of arrangement, leave someareas of the hoop barn, including the feeding area,un-wetted to give animals a choice of environments.Pigs may have a tendency to lie on bare concrete toremain cool, but wetting the concrete feeding areawill encourage the pigs to lie in the feeding areamore, making it difficult for the animals to haveaccess to feed. Allow 5 to 6 square feet per pig whendetermining the area to be sprinkled.

Wetting of the pigs should be done using a cycletimer to allow evaporation of water from the pig’ssurface to enhance the cooling effect. Sprinklersshould put out large droplets instead of a mist. Largedroplets are designed to cool the pigs; misters aredesigned to cool the air immediately above the pig.Nozzles that emit large droplets are preferredbecause the pig can select its rate of cooling byposture and location. Also, misters depend in parton airflow and lose some effectiveness when therelative humidity in the pig zone where the mistersare spraying is at or above 75%.

Timers should be set to operate anytime thetemperature exceeds 80-84F, and they should turn

sprinklers on for 1 or 2 minutes out of a 10- to 20-minute period. Specific settings will vary withclimate, pig size, humidity, temperature, wind, andwater pressure, but the critical issue is wetting thepigs and then allowing them to dry and cool as thewater evaporates. Producers will have to experimentwith several settings to find the right one for aspecific location. The goal is to wet all the pigs in 1to 2 minutes and then allow them to dry. Just asthey become dry, the water should turn on again.

If electricity is not available, sprinklers will haveto be managed manually, or there may be optionsusing solar or battery-operated controllers. In eithercase, the producer must observe the pigs frequently,adjust the system accordingly, and avoid allowingpuddles to form in the bedding. Careful managementis necessary to prevent problems with wet beddingand inadequate drying time, but pigs digging holesin the bedding pack has not been a problem whenwetting devices are managed properly.

Feeders and WaterersHoop barns usually use self-feeders like the ones

depicted in Figure 12, and feeders are often used asfeed storage devices as well. In a grow-finishoperation, provide a feeder space for every five toten pigs. Some producers have used less feedingspace (more pigs per hole) with success, but otherproducers have reported problems. The quality, orwidth and depth of the eating space, defines thenumber of pigs per space. If large feeder spaces(more than 12 inches wide) are provided, more pigscan use that space. However, if the feeder spaces

Figure 12. Use self-feeders in a grow-finish

hoop barn.

In a grow-finish operation, provide a feeder space forevery five to ten pigs. A typical 180- to 200-head hoopstructure has two or three large self-feeders. Providingsufficient feeder space is relatively inexpensive andprobably will be cost effective in the long term.

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are smaller and restrict access due to width (a typical270-pound pig is 13 inches wide at the shoulder) orrestrict head movement during the ingestionprocess, more eating spaces need to be provided.

Providing sufficient feeder space is relativelyinexpensive and will be cost effective in the longterm. A typical 180- to 200-head hoop barn has twoor three large self-feeders and one, four-hole, no-freeze waterer. In the summer, additional wateringspace is necessary, and this is typically provided byone or more nipple waterers.

Animal ManagementOne major way in which the management of

hoop barns differs from the management ofconfinement facilities is the use of large amounts ofbedding. This difference necessitates acquiring thebedding, putting it in the structure, and hauling theused bedding away.

Because the pigs are in a large group in a beddedsetting, they may be hard to locate. The producermust actually enter the bedding area at least dailyand check all the pigs; checking the pigs by simplylooking into the structure is inadequate.

Other management strategies are the following:• Because the pigs are in one large pen, hoop

barns must be managed as all-in-all-outunits. They cannot be operated ascontinuous flow units.

• After the structure is cleaned during thewinter, the floor must be heavily beddedimmediately to prevent the ground fromfreezing.

• In addition to initial application of bedding,bedding must be added regularly tomaintain a dry environment.

• Freeze proof waterers are necessary.• Lights may need to be added for observing

animals after dark.

Pig PerformanceWith all housing systems, haphazard or careless

management will usually lead to poor pigperformance, but because management needs aredifferent in hoop barns than in confinementfacilities, performance and management may bemore closely linked in hoop systems than inconfinement systems.

While the hoop barn provides a dry and draft-free environment and the bedding aids the pig increating a desirable microenvironment, there may

be seasonal differences in pig performance,particularly in northern climates.

Producers report that behavioral vices areoccasionally present in hoop-raised pigs. These vicesinclude ear necrosis, tail biting, and naval suckingin small pigs. Experience suggests that these vicesare usually a signal that additional, high quality,dry bedding is needed.

Growth

In the Midwest, feed intake is often greater inhoop barns than in confinement barns, particularlyin the winter. The amount of additional winter feedvaries between farms, climate, and seasonalextremes. Research at Iowa State Universityresulted in winter feed intake that was almost 10%more in hoop barns than in confinement facilities.Typically, for the first one or two uses of a hoop barn,the producer provides the same diet as for pigs inconfinement barns until a clear pattern of elevatedfeed intake emerges. Some producers are beginningto adjust diets for nutrient density with anexpectation of elevated feed intake.

During the winter in the Midwest, a goodestimate is that 0.3 pound more feed will be neededper pound of live weight gain, or about 10% morefeed compared to the amount of feed needed inconfinement barns. During the summer in theMidwest, a good estimate is that there will be nodifference. For a yearly estimate in the MidwesternUnited States, use 0.15 pound more feed per poundof gain in hoop barns. Based on ISU research resultsand on producer experiences in both winter andsummer, backfat is estimated to average 0.05- to.10-inch more at the tenth rib for pigs raised in hoopbarns compared to pigs raised in confinement.

Average daily gain for hoop-housed pigs is similarto the rate of gain of confinement pigs and may be asmuch as 4% more during the summer if adequatecooling is lacking in confinement facilities.

A majority of producers report a three-weekmarketing range if the pigs grouped in a hoop arewithin one week of age. That is, the time from thesale of the first pig to the removal of the last pig isabout three weeks. For 195 pigs, this usually meansthat approximately three to five pigs do not reachminimum market weight. These results are similarto those obtained in confinement operations.

The percentage of pigs that die or are euthanized(mortalities), that are marketed alternativelybecause of a detrimental condition (culls), or thatare marketed to the packer but are less than an

12

acceptable weight (lights) does not differ betweenhoop barns and confinement buildings.

Research at ISU has been conducted related tooptimum stocking density of finishing pigs in beddedhoop barns. In a study comparing 9, 10.5, and 12square feet per pig, the pigs with 9 square feet grewslightly slower (about 2-3%) and ate less feed (about4%) than pigs with 10.5 or 12 square feet in beddedbarns. Results from the study suggest that 9 squarefeet per pig in bedded barns results in poorer pigperformance and economic returns and thatallocating 11 square feet per pig may be the bestcombination of pig performance and economics. Asthe stocking density increases, that is as pigs are morecrowded, the research also observed more dungingon the feeding platform.

Meat quality

Pigs from hoop barns typically have a lowerdressing percentage or yield (approximately 1%) lessthan that of confinement-fed pigs. This may be dueto slightly greater feed intake, consumption of somebedding, or larger meals because of the larger groupsize. Some data suggests that pigs raised in coldclimates also have larger internal organ size, whichalso contributes to a reduced dressing percentage.Hoop-reared pigs, therefore, will need to bemarketed at slightly heavier live weights (about 2or 3 pounds) to achieve the same carcass weight aspigs raised in confinement.

The quality of fresh pork dictates the suitabilityof pork for use as a fresh product and furtherprocessing. Pork color, water-holding capacity andtexture are among the important characteristicsthat domestic and international customers use todefine pork value. These traits are under theinfluence of the response of muscle during the earlypostmortem period (0-24 hours). During this period,glycogen is converted to lactic acid in muscle and aconcomitant increase in the acidity of the product(measured as a decrease in pH) is observed. A rapiddecline of pH during the first few hours afterslaughter is especially detrimental to proteins thatdetermine the color and water holding capacity ofpork. Because there is a direct relationship betweenultimate pH and pork water-holding capacity, theextent of pH decline also has the potential toinfluence pork quality.

Enriching the production environment can alteranimal and tissue response to stress of handling andtransport. Decreasing pen density and providingbedding can enrich production environments and

can alter the amount of pen-mate directed behavior.A change in the behavior has the potential to alterthe pigs’ response to the period before slaughter andthus pork quality. Previous reports have shown thatenvironmental enrichment can improve pork water-holding capacity and tenderness. The preciseexplanation for this improvement is not currentlyknown. The influence of hoop systems on ultimatepork quality is currently under investigation.

Health

The health of pigs in hoop barns appears to bevery good. Studies report that death loss has beenminimal in hoop barns. Respiratory problems havebeen minimal. To date, experiences have shown thata wide variety of pig genetics are adaptable to hoopbarns. With repeated use of the structure, pathogensmay build up in the soil under the bedded pack, or ona concrete floor if it has not been cleaned thoroughly.Roundworms can be an additional long-term healthmanagement concern if the pigs are not wormed orparasite free before entering the facility. Concretefloors can be pressure-washed between groups,although not all producers may find this necessary.A routine monitoring program for internal parasitesis essential, and a monitoring program for externalparasites also is recommended.

Animal HandlingTo facilitate animal handling, a hoop barn needs

to have a good gating system with some type ofsorting area. The gating system must make possiblethe following activities:

• Sorting animals for market.• Holding back smaller animals not going to

market.• Separating sick animals from the larger

group.

When handling large groups of finishing pigs itis important to remember several behavioralprinciples. Pigs are social animals, and thereforeprefer to be around other pigs. With these behaviorsin mind, design a handling facility so that pigs alwayscan see other pigs, which promotes movement of pigsthrough the handling facility. Pigs will synchronizetheir behavior such as walking, running, and lyingdown and will follow the leader of the social grouping.When stock people are moving pigs, it is essentialthat they keep this in mind.

Pigs can be moved out of a hoop barn using awide plastic tarp (approximately 30 feet long and 3

13

feet wide). One stock person holds each end, andthey use the tarp like a moving fence.

An alleyway across the front of a series of hoops toa holding pen also is very useful for sorting and handlingpigs. Figure 13 shows a typical arrangement of barnsand holding and loadout areas. Sometimes workingchutes, like the example outlined in Figure 14, are addedto help with routine management and sorting.

A working chute should curve to promote pigmovement, as pigs can always see other pigs ahead,and there are no sharp angles. Single and doublewide chutes are suitable.

The holding pen holds approximately 195market pigs, which is the usual number of pigs keptwithin a single 30 x 72 hoop barn. A common practicewhen handling the pigs is to sort the pigs in groups

Figure 14. A working chute, such as this, allows pigs to be loaded with minimal stress to pigs and less effort by

the stock person.

Figure 13. A common concrete area with proper gating can allow easy sorting.

14

of approximately 20, and then reload the sorting penwith another group of pigs. Moving small groups ofpigs at a time appears to promote pig flow.

Portable loading chutes are effective for loadingmarket animals if one to three hoop barns are beingused. If an operation has more than three hoopbarns, a permanent loading facility is more efficient.

To promote pig movement during loading, theloading ramp should be designed so that the pigsmove in single file or side by side, so they can’t turnaround. In addition, the ramp has stair steps tominimize slipping, and is free of sharp edges to avoidbruising.

Because of the layout of hoop barns and largegroup sizes, identifying, removing, and/or treatingsick animals can be difficult.

BeddingBedding management and the labor involved are

two factors that are important in making hoop barnsoperate efficiently. Lack of sufficient bedding cancause stress in the pigs, and bedding is one of thebiggest keys to the success of winter production inhoop barns. Trials in Iowa showed that summergroups required about one-third less labor per pigthan the winter group because of less bedding (aboutone-third less bedding in summer) and less manureto haul.

However, the bedding creates distinct labordemands in a hoop barn. Because of the bedding, moretime is spent checking pigs, that is, walking throughthe bedded area. More time also is involved incarefully locating and observing sick animals becausesick pigs tend to stay burrowed in the bedding. Timeis also spent moving bedding material and loadingand hauling solid manure.

Provide enough bedding to keep the floor underthe bedding pack relatively dry. Pigs will establishcertain dunging areas throughout the structure.Many times, winter groups will sleep in the far backand along the sidewalls and dung in the spacebetween the bedding area and the concrete slab usedfor feeding and watering, although sometimes thedunging area is concentrated along the cool northernwalls.

Wherever it occurs, additional bedding will berequired to prevent the dunging area from becomingsloppy. If the dunging area becomes too wet, pigsmay not be as willing to go to the feeder. Excessmoisture, whether from dunging, leaky waterers,or heavy sprinkling for summer cooling, can leachnutrients out of the bedded pack. Such leaching will

lead to elevated levels of N and K in the soil andgroundwater beneath earthen-floored structures,another reason to ensure adequate bedding and toconsider an impermeable concrete floor. The manureand bedding mixture will accumulate to a depth ofthree to four feet in portions of the structure duringwinter groups.

The combination of moisture and additionalnutrients from urine and dunging stimulate microbialdecomposition of the bedded pack. In the wet dungingareas, this decomposition is anaerobic. In unsaturatedareas of the bedded pack, aerobic decomposition alsowill occur, which reduces odors and methane emissionsand generates heat. This heat production increasestemperatures in drier areas of the bedded pack duringsummer and winter conditions, respectively.

Cooling sprinklers and reduced bedding rates canhelp keep the bedded pack from overheating insummer conditions. Somewhat higher bedding ratesand lower humidity during the winter result inincreased heat production, allowing the pigs to findwarm areas to rest on and burrow into on cold winternights. The comfort the pigs receive from the beddingamounts to an effective temperature increase ofapproximately seven degrees over the actual airtemperature. However, because of the heating of thecomposting bedding pack and the effect of huddling,the actual effective temperature may be as high as25 F or more over the air temperature. This dependsupon the bedding condition and the ability of the pigto burrow into loose bedding.

Several materials have been used successfullyfor bedding, including baled corn stalks and wheatstraw. Bedding use is seasonal with the largestshare used in cold weather, but on an annual basis,most producers use about 195 pounds of baledstalks per pig marketed to maintain dry bedding.Producers in warmer regions report using sand forbedding. Table 3 lists other products that could beused, along with the approximate amount ofbedding needed.

While the selection of bedding is based mostly onwhat is readily available, many other concerns shouldenter into the decision. These concerns vary fromregion to region and include the following:

Soil conservation: In some places in theMidwest, much of the agricultural land base isclassified as highly erodible. Many producers havesigned an agreement as part of their conservationplan with the federal government that they willmaintain a certain residue level after planting. Useof large amounts of residue in a bedded livestock

15

system such as hoops has raised the followingconcerns:

• From how many acres do I need to harvestresidue? Corn stover residue weight isapproximately equivalent to grain weight, soa 150-bushel/acre cornfield will generateabout 4 tons of stover per acre. Similarestimates can be made for other cropresidues, based on yield and the harvestindex (the grain to residue ratio varies fordifferent crops). Harvest losses andconservation constraints can reduce thispotential by 30 to 50% or more.

• How much residue can I remove per acre andstill comply with my conservation plan? Thisdepends on site-specific calculations, andwill be strongly influenced by tillage, slope,and crop rotation. Higher removal rates arepossible with no-till on relatively flat fields,and are increased if rotations includeperennial crops or forages.

• If I intend to plant using no-till, will I beable to land-apply the residue in a thinenough and uniform enough pattern withexisting manure spreaders so as to minimizeplanting problems?

• What is the fertilizer value of the manureand residue mixture?

• Substantial organic matter will be returnedto the crop land, but will a high carbon-to-nitrogen (C:N) ratio prevent the nitrogen

from being fully available for crop use thefirst year following land application?

• Is sufficient space available to store themanure safely and legally when land isunavailable for spreading?

Custom baling: Custom baling of residue stalksmay be expensive, costing between $7 and $15 per bale.Additional costs are incurred in transporting bales.On-farm baling, while requiring less out-of-pocketexpense, is not a low-cost option. Additionally, stalkbaling results in more wear on round balers than doesnormal hay baling.

Bedding availability: During years in whicha wet fall or early snow prevents stalks from beingbaled in a timely manner, they may become lessavailable and more costly. A situation of this typecould require a shift in priorities from doing all ofthe grain harvesting first to a system of harvestingand baling stalks. An alternative is to plant a portionof the field crop acreage with a crop such as barley,wheat or oats that produces a summer residue.

Bedding storage: In regions with cold andrelatively dry winters, bedding baled in the fall andused before the spring generally does not deteriorateif stored outside. However, if stored under warmand damp conditions, bedding must be protected toprevent reduction in its quality. In the MidwesternUnited States, bales that will be used during springand summer should be stored under cover on a welldrained area. Bales stored outdoors will lose beddingquality, thereby increasing costs.

Producers are reporting that winter use requires30 to 40 big round bales (1,200-pound bales) ofshredded corn stalks per group of 195 pigs. Thetypical method of employing bedding is to begin a setof pigs with eight bales of bedding already in thestructure, and then to add an average of two balesper week in winter. Summer use will be less. Table 3shows estimates of the amounts of various beddingtypes needed at different times of the year. Thebiggest key to success appears to be using lots of highquality bedding. The major reports of behavioralproblems come from producers who have restrictedbedding additions.

The cost of bedding will vary by region, butproducers should expect that the cost of bedding willbe $1.50 or more per pig for winter use. Besidesshredded corn stalks, some producers have usedsoybean stubble bales successfully. Other producershave used barley straw, wheat straw, oat straw,prairie hay, and spent turkey litter as bedding

Table 3. Estimated amount of bedding needed for

pigs in a hoop barn.

Average Amount Amount

Amount of of

of Yearly Summer Winter

Bedding, Bedding, Bedding,

Material Used lb per pig lb per pig lb per pig

Shredded corn stalks 195 125–150 200–250

Corn cobs 240 150–180 240–300

Barley straw (long) 240 150–180 240–300

Oat straw (long) 180 110–135 180–225

Wheat straw (long) 225 140–170 225–285

Sawdust (hardwood) 335 210–250 335–415

Sawdust (pine) 200 125–150 200–250

Wood shavings(hardwood) 335 210–250 335–415

Wood shavings (pine) 250 155–190 250–315

16

sources. Wood product residue should be used withcaution. Shavings and sawdust need to go througha heat cycle to avoid the transmission of aviantuberculosis to the pigs. Unless wood product residuehas gone through a heating process, there is a riskof carcass condemnation at slaughter.

Producers who use big round bales as beddingreport they use a spear point on a hydraulic loader.They lift the bale through the rear opening, cut thestrings, lower the bale, and unroll the bale down themiddle of the bedding pack. (See Figure 14). Thistakes 10-20 minutes per bale. As the pigs get older,many producers simply set bales on end and let thepigs unravel the bales. In all cases, strings must beremoved from the bales so pigs will not ingest themor become entangled in them.

In hoop barns, prevent the bedded pack fromexpanding into the feeding and watering area byelevating the feeding and watering area 12 to 18inches above the bedded area. Figure 15 illustratesthis concept. Early in a cycle, smaller pigs may havedifficulty going from the feeding-watering area tothe bedded area; if they do, most producers just stacksmall bales or mound the bedding thickly enoughfor pigs to access the feeding area.

Manure HandlingEach time a group of pigs is finished, all of the

bedding and manure must be removed. Reusing thebedding may reduce the sanitation in the structureand carry over some pathogens from previousgroups. Letting the building surfaces thoroughly dryout between groups can help reduce the potentialfor pathogen carry-over.

In the winter it is important to apply newbedding shortly after cleaning, before the floor ofthe hoop barn can freeze. Frozen ground or coldconcrete will chill the next group of pigs by rapidlydrawing the heat from the pigs’ bodies. A fresh layerof bedding can insulate an earthen or a concrete floorfor several days or even weeks (depending ontemperatures) until the next group of pigs arrives.

The best equipment to remove the bedding packis a mechanical, front-wheel assist tractor with agrapple fork attachment on the front end loader. Atractor-loader with manure tines on the bucketgenerally will work; although, it can take some effortto break apart the bedded pack, and a standard skid-steer loader may not be sufficient. One producerreports using a chisel plow to disrupt the beddingpack before clean out. Most producers agree on 10to 15 hours of total labor to clean the hoop barn and

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Figure 14. Large round bales used for bedding.

Weekly additions of fresh bedding are necessary for pigcomfort and good performance.

Figure 15. Concrete step to separate the elevated

feeding area from the bedded area.

spread the material on nearby crop land. Below is alist of some of the challenges that may exist withmanure handling:

• Fewer custom solid manure haulers areavailable in some parts of the Midwest. Thismay require that a manure spreader, loader,and tractor will need to be available for on-farm usage.

• The properties of the manure vary greatlythroughout the structure. Because of this, thefertilizer value of the manure is difficult toestimate accurately and properly credit fornutrient content in a manure managementplan. Mixing loads to balance material fromdunging and resting areas can partiallyalleviate this concern, as can composting.

17

• Depending on the time of year, space may beneeded to store the manure safely andlegally until land is available for spreading.Storage and composting sites should bedesigned to minimize runoff and associatedwater quality concerns. A roof shelter andimpermeable surface are ideal, while runoffcollection ponds and/or vegetative filterstrips may be required in some situations.

• Used corn stalk bedding is not easily handleddue to the potential for wrapping on manurespreader beaters. This can exacerbateproblems with spreader uniformity, and befrustrating to clear and clean.

• Minimum tillage cropping systems mayhave difficulty with irregular manuredistribution following land application of themanure, especially if the manure has notbeen thoroughly mixed following removalfrom the hoop or if the residue used asbedding has not been chopped to reducestraw or stubble length prior to placementin the hoop. This can be a particularchallenge for no-till planters when manureis applied in the spring.

• Substantial organic matter will be returnedto the crop land, but unstabilized carbon inbedding can reduce nitrogen availabilityduring the first year after application, andin extreme cases cause net Nimmobilization, which can actually reducecrop yields. This problem most often ariseswith heavily bedded manures applied in thespring.

Composting manure

Several of these challenges, including lack ofmanure uniformity, interference with minimum tillplanters, and the risk of N immobilization, can begreatly reduced by composting the bedded pack priorto spreading. Bedded hoop manure is easy to compost.Unlike many manures, the bedded pack from hoopbarns typically has appropriate moisture andadequate porosity to be composted without anyadditional bulking material. Simple windrow piles,about 5 to 7 feet high and 10 to 15 feet wide, willcompost with minimal management.

Turning is not necessary, although it willenhance weed seed and pathogen destruction andprovide a more uniform product. Within two to threemonths the volume of the manure will be reducedby 50 to 60%, with similar weight losses unless

precipitation is high. These reductions in weight andvolume reduce hauling requirements considerably,which helps compensate for the additional handlingand management.

Manure composting windrows also can be usedfor mortality disposal, as long as the carcasses arewell buffered on all sides. About 18 inches of composton the bottom, sides, and top of the mortalities areusually sufficient to eliminate odors and attractionof varmints. Piles with mortalities should not beturned until the carcasses degrade, which usuallytakes several weeks. Some states have specific rulesor guidelines for manure or mortality composting,so it is important to check for regulatory compliance.

The typical bedded pack in a hoop barn used forfinishing pigs is higher in nitrogen than is normallyrecommended for composting, with a C:N ratio av-eraging between 11:1 and 16:1 as opposed to the 25:1or 30:1 that is considered ideal. This relatively lowC:N ratio reflects 1) the relatively high N content ofswine manure, and 2) the biodegradation that hasalready occurred in place within the bedded pack,which includes losses of both C and N. This low C:Nratio results in significant N losses duringcomposting (about 20% of excreted N), although thisis less than has already occurred within the beddedpack (about 55% of excreted N).

Manure characteristics

Cumulative losses of hoop manure nitrogen,about 75% of the excreted N, are high relative toslurry manure storages and slightly less than occurfrom anaerobic lagoons. Most of these losses arevolatile N compounds, including ammonia andnitrous oxide, although leaky waterers within thestructure or rainfall on composting piles can resultin runoff and leaching losses of ammonium andnitrate. The other macronutrients P and K are betterconserved, although cumulative losses of theseelements can reach 20 to 40% in outdoor compostingsystems if runoff and leaching are allowed to occur.

Because of differences in bedding type andmanagement, the nutrient content of the bedded packand subsequent compost can vary widely. Table 4illustrates mean values and ranges for dry mattercontent and N, P, and K for fresh hoop manure atthe time of cleanout and after several months ofcomposting. Values are presented in lbs/ton (to helpcalculate application rates) as well as percentage ofdry matter.

The first four columns of data are summarizedfrom several hundred samples from hoops, a

18

demonstration farm, and eight different commercialfarms. The wide range reflects both seasonaldifferences in bedding rates as well as differentmanagement styles. The final column, which showsmeans and standard deviations in pounds per pig,can help project manure weights and nutrientquantities based on pig production. This column ismore consistent, because reporting on a lb/pig basisto some extent normalizes for different beddingrates. Adding more or less bedding has a strongeffect on nutrient concentrations (reflected in lbs/ton and % dry matter), but the low nutrient contentof the bedding has less effect on the overall nutrientamount (lbs/pig).

Because application rates are dependent on themore variable concentration data, it is important toget a site specific manure analysis for an accuratemanure management plan. Given the variability inthe bedded pack, composite samples that includesubsamples from different depths and regions in thebedded pack are particularly important whensampling hoop manure for analysis.

The values in Table 4 reflect total nutrientcontent, and, as with other organic amendments, notall of these nutrients will be available in the firstgrowing season. P and K availability has not beenstudied for hoop manure or the resulting compost,but based on results for similar organic amendments60 to 80% availability is likely in the initial year.Nitrogen availability has been investigated, andresults indicate about 25 to 30% of the nitrogen willtypically be available in the first year. Although theN availability was similar for both fresh andcomposted hoop manure applied in the fall, thepreviously mentioned immobilization problem can

reduce or eliminate short term N availability for freshhoop manure applied before planting in the spring.Composting will eliminate the risk of Nimmobilization, and thus is recommended whenhoops are cleaned out in the spring. However, theadditional losses during composting do reduce thetotal nutrients available, so in areas with adequatecropland available, hoop manure from fall cleanoutsprobably is best applied fresh.

ComparisonsTo get a better sense of how hoop barns compare

to confinement buildings, many aspects such as laborrequirements, pig performance, building life, andbedding costs need to be examined. Carcass qualityalso can affect the packer’s offered price. Knowledgeof these items will enable producers to compare hoopbarns to other options.

Labor requirements

Labor requirements are a highly variable input toswine production systems. Labor varies from farm tofarm depending on the layout, level of automation, ageand condition of facilities, and other factors. Table 5shows some estimated amounts for general labor andmanure handling.

Studies of labor needs for hoop barns showslightly more labor needed than needed forconfinement systems. Labor needs are slightly higherprimarily because large bales of bedding must behauled and placed into the hoop barn. The totaldifference is estimated at about 0.05 hour/pig, orapproximately 4 minutes more per pig.

The type of labor, however, is quite different forhoop barns compared to the labor needs associated

Table 4. Characteristics of fresh and composted bedded manure from swine finishing hoops.

Note that all nutrients are on an elemental basis (N, P, and K; not P2O5 or K2O).Mean Range Mean Range Mean ± Std. Dev.

lbs/ton % (dry basis1) lbs/pig

Fresh hoop manure

Dry matter 700 540– 1180 35 26– 59 270±105Nitrogen 15.4 8– 25 2.2 1.5– 2.8 7.3±1.2Phosphorous 6.9 5 – 8 1.0 0.6– 1.4 2.9±0.8Potassium 15.1 12– 21 2.1 1.7– 2.4 6.4±1.2

Compost

Dry matter 1020 650– 1530 51 24– 67 200±34Nitrogen 19.6 13– 35 1.9 1.2– 2.8 4.2±0.9Phosphorous 11.9 9– 25 1.2 0.9– 2.2 2.3±0.6

Potassium 20.1 19– 36 2.0 1.0– 3.0 5.1±1.21 Values are reported on a dry basis, except dry matter content which is reported on a wet basis.

19

with typical confinement facilities. It includesbedding the pigs, checking the pigs, and cleaningout the bedding pack. Walking the bedding areatwice daily to check pigs is crucial; with large groupsof deep-bedded pigs, consistent observation of pigsis critical for success.

Cost analysis

Table 6 shows a cost analysis comparing con-finement and hoop barns. Costs vary depending onlocation and availability of materials, so you areencouraged to prepare your own budget in the “YourEstimate” column of Table 7 with values that reflectyour operation. Use Tables 5 and 6 to help estimateyour costs.

The comparisons in Table 6 use a cost of $180per pig space for a confinement system compared to$62 per pig space for a hoop barn. The confinementsystem is 7.5 square feet per pig while the hoopsystem is 11 square feet per pig. Investment inmanure and feed handling equipment is the samefor each system. Again, depending upon alterationsin system design, location, or other individualcharacteristics, these values may differ for youroperation. The average daily gain will be the samefor both systems: 1.7 pounds per day. The budgetis calculated based on pigs being placed in thefacility at 50 pounds and fed to 265 pounds or 215pounds of gain. Thus, on average, pigs aremarketed in 126 days. However, this means that50% of the pigs are marketed in the 10 day periodprior to the 126-day average and the other 50% aremarketed in the 10 day period after the 126-dayaverage. Add a 7-day clean out period between groupsof pigs, and the total time per group of pigs is 143

Table 5. Estimated amount of labor requirements.

Labor Labor

Requirements Requirements

Average, Range,

hr per pig hr per pig

Confinement

General labor 0.20 0.14–0.25Manure handling 0.04 —

0.24

Hoop barn

General labor 0.24 0.18–0.30Manure handling 0.05 —

0.29

days (126 + 10 + 7). This equates to 2.55 turns peryear with each system.

Fixed costs are calculated at 12.2% of investmentfor a confinement facility and 15.2% for the hoop fa-cility. The interest rate is 8% on average investment(4% on initial investment), with insurance and taxes

Table 6. Estimated costs.

Facility Investment (FI) Average Range

Building costConfinement (per pig space) $180 $160–$200Hoop structure (per pig space) $62 $60–$65

Feed and Manure Handling Equip.(per pig space) $36 —

Fixed Cost

DepreciationConfinement andEngineered Hoop Building

(of Fixed Investment) 6.7% —Non-Engineered Hoop Building

(of Fixed Investment) 10.0% —Interest (of Fixed Investment) 4.0% —Insurance and Taxes

(of Fixed Investment) 1.5% —Total Fixed Cost

Confinement andEngineered Hoop Building

(of Fixed Investment) 12.2% —Non-Engineered Hoop Building

(of Fixed Investment) 15.5% —

Operating Cost

Fuel, Repairs, UtilitiesConfinement (per pig marketed) $1.39 —Hoop structure

(per pig marketed) $1.04 —Bedding (per pig marketed) $2.44 $2.20–$2.70

Feed Efficiency (FE)Confinement 2.9 2.80–3.0Hoops 3.05 2.9–3.2

Feed Cost (per lb. of feed) $0.06 $0.05–$0.07Vet/Medical (per pig marketed) $1.56 $1.25–$2.00Marketing/Misc. (per pig marketed) $1.53 $1.00–$2.00

Miscellaneous

Moving round bales (per bale) $2.00 $1.00–$3.00Grinding, mixing feed (per ton) $6.20 $3.50–$10.00Surface spreading liquid manure

(per hr) $33.75 $30.00–$45.00Hauling and injection (per gal.) $0.0088 $0.0050–$0.012Hauling and surface broadcast

(per gal.) $0.0079 $0.0050–$0.010Irrigation (per gal.) $0.0057 $0.0040–$0.008Umbilical (per gal.) $0.0070 $0.0060–$0.010Loading solid manure (per hr) $31.35 $25.00–$35.00Loading, spreading solid manure

(per hr) $42.45 $40.00–$50.00Farm labor (per hr) $10.00 $7.50–$12.50

20

Pigs raised in hoop facilities ate 4.5% more feed thandid the confinement-raised pigs. Again, location canaffect these values, as feed efficiency tends to beaffected the most during the winter months in thenorthern climates. Labor requirements, includingmanure removal, are 14 minutes (.24 hour) per pigfor confinement and 17 minutes (.29 hour) per pigfor the hoop barn.

The confinement pigs had a greater leanpremium. It was $.45 per pig or $.18 per cwt liveweight. This may be affected by the type of geneticsused in hoop or confinement facilities.

As this comparison shows, total costs per pig arequite similar between the two systems. Managementis important for both systems. Differences betweenproducers in management preferences and/orcapabilities may tip the scales toward one system

at 1.5% for both facility types. Keep in mind thatthe initial cost of an engineered hoop barn willbe higher than the cost of a non-engineered hoopbarn. Life expectancy, on average, is 15 years fora confinement building. Life expectancy for thehoop barn is 10 years.

Fuel, repairs, veterinary/medical, and othercosts are based on Iowa State University data. Thebedding cost is for the rate of 195 pounds of shreddedcornstalks per pig. The bedding use is about 0.9pounds per pound of live weight gain. A 1,200-poundbale at $15.00 per bale provides a cost of $0.0125per pound of residue. Interest is at 8%, covering 4months for the feeder pig and 2 months for the otheroperating costs, excluding labor.

Feed efficiency is 2.90 pounds of feed per poundof gain in confinement and 3.05 for the hoop facility.

Table 7. Swine grow-finish cost comparison.

Item Hoop Confinement Difference Your Estimate

Facility Investment

Building (per pig marketed)(2.55 turns per year; $180 per pig space for confinement;

$62 per pig space for hoop) $24.31 $70.59Feed and manure handling equipment (per pig marketed)

(2.55 turns per year; $36 per pig space for confinement;$36 per pig space for hoop) $14.12 $14.12

Total Investment (per pig marketed) $38.43 $84.71

Fixed Cost

Interest, taxes, depreciation, insurance (12.2% of totalinvestment for confinement; 15.5% of total investment for hoop) $5.96 $10.33 $4.37

Total Fixed Cost (per pig marketed) $5.96 $10.33 $4.37

Operating Cost

Feeder pigs (50 lb) $42.00 $42.00 $0.00Interest on feeder pig (10% for 4 months) $1.40 $1.40 $0.00Fuel, Repairs, Utilities $1.04 $1.39 $.35Bedding $2.44 0 -$2.44Feed

Confinement (215 lb gain @ 2.90 F/G @ $0.06 per lb feed) $37.41Hoop (215 lb gain @ 3.05 F/G @ $0.06 per lb feed) $39.35 -$2.44

Vet/Medical $1.56 $1.56 $0.00Marketing/Miscellaneous $1.53 $1.53 $0.00Interest on Fuel, Feed, etc. (8% for 2 months) $0.61 $0.56 -$0.05Labor

Confinement (0.24 hr per pig @ $10.00 per hr) $2.40Hoop (0.29 hr per pig @ $10.00 per hr) $2.90 -$.50

Total Operating Cost (per pig marketed) $92.55 $87.97 -$4.58

Total Overall (per pig marketed) $98.51 $98.30 -$.21

Total Cost per 250 lb market animal (per CWT* live) $37.17 $37.09 -$.08

Lean premium (per CWT live) $0.60 -$0.60

Net Cost (per CWT live) $37.17 $36.91 -$0.26

*CWT = hundredweight

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or the other. Increases in confinement facility orinvestment costs would favor a hoop barn system.Similarly, increases in fuel, utilities, or repair costswould favor the hoop barn. Hoop barns also havean advantage when feed costs are low, confinementbuilding prices are high, initial capital is limited,and bedding is cheap.

In other cases, confinement buildings may be abetter economic alternative. Increases in prices forbedding, feed, or labor would create an advantagefor a confinement system.

Niche markets that require specific housing sys-tems are also a possibility. When evaluating sys-tems it is necessary to evaluate specific opportunitiesand potential premiums that may be possible withthe system. It is necessary to evaluate both the coststructure and the premium structure.

Note that an engineered hoop barn will have alonger life and a lower fixed cost percentage than anon-engineered hoop barn. Depending on the initialcost, an engineered hoop barn could have an economicadvantage over both a confinement building and anon-engineered hoop barn.

Financial analysis

Table 7 provides a comparison of a hoop facilitywith a confinement facility. The comparison providesmixed results. Hoop facilities provide a superior rateof return on initial investment, internal rate of re-turn, and modified internal rate of return, along witha shorter pay back period. These advantages can beattributed largely to the hoops’ lower initial invest-ment. The confinement facility has the advantageof a longer service life as well as higher net profitsper pig per year. The confinement facility has anadvantage of a higher net present value. This meansthat hoop operations will have to invest in more pigspaces in order to return the same net present value.

Evaluating the systems based on theirsensitivity to market conditions and productivityalso yields mixed results. Due to its lowerinvestment, shorter service life, and lower net profitper year, the hoop facility is more sensitive tochanges in hog prices, facility costs, and productioncosts. However, the confinement facility is moresensitive to changes in the cost of capital due to itslonger service life and higher initial investment.

An evaluation of the effect of a change in thefeed ration price on return on investment shows thatthe hoop system is more sensitive to changes inration costs. This is expected given that more feedis needed for pigs in hoop systems due to their poorer

feed efficiency. Rate of return on investment is equalbetween the hoop and confinement facility at aration cost of about $.08 per pound.

Market hog carcass price also affects rate ofreturn on investment. Return on investment for thehoop system is more sensitive to market hog pricesthan it is for confinement systems. At a carcass priceof about $54.00 per hundredweight, the return oninvestment is equal between the two systems. Atlower carcass prices, the rate of return oninvestment is higher for confinement systems. Forcarcass prices above $54, the rate of return oninvestment is higher for hoop systems.

This makes the question of which system is abetter financial investment dependent on severalissues. The producer must consider the availableamounts of initial capital, operating capital, landfor manure application, labor available, and pig flowin order to decide which is the better investment.The operator also must consider the cost of capital,value of alternative capital uses, market specifics,and risk aversion, as well as the intrinsic value thatthe alternatives have.

Other considerations

For diversified, moderate-sized swine produc-ers, hoop barns offer some additional considerations.Hoop barns create opportunities for producers toparticipate in certain niche markets, which pay apremium over the commodity price level. Produc-ers using hoop barns need to check all the specifica-tions for a particular market, but niche markets suchas organic, natural, humanely reared, reared withbedding, reared on family farms, or combinations ofthese attributes appear to offer additional market-ing outlets for hoop-raised pigs. Many of these mar-kets require specific housing systems such as hoopsin order to participate in the market.

The structures themselves are versatile andcould be used for alternative purposes, such asstoring hay, machinery, or grain. The hoop barnsmay be constructed with on-farm labor. Theversatility, production flexibility, and low capitalcosts may result in reduced financial risk. Thequality of the work environment is generally good,with no liquid manure and a large volume ofnaturally ventilated air inside the barn. Manurecan be stockpiled for spreading at other times.

The bedded-pack requires solid manurehandling equipment, which some producers preferbut others do not. Because of the added bedding andhigh solids content, manure can easily be stockpiled

22

or composted for spreading at other times. However,the added bedding increases the volume of solidmanure, which can increase hauling costs. Somebedding may need to be protected from adverseweather for use later in the year. Low cost, highquality bedding must be a high priority for thesystem. Also, it is unclear whether pathogens willbuild up under the bedding pack over long periodsof use.

Following is a summary of the concerns andpossible limitations to be examined when consideringhoop barns.

• How often does the tarp need to be replaced?• Can I insure this building against wind

and hail damage?• What types of bedding can be used?• Will storage be needed for bedding?• What provisions are needed to prevent

leaching and runoff from stored orcomposted manure from polluting groundor surface water?

• Will there be pathogen buildup under thedeep-bedded area?

• Will heat from the decomposing manurepack cause problems for the pigs in hothumid weather?

• Will manure spreading and residueharvesting equipment need to be purchasedas an added expense?

• How much decrease in lean premium willresult due to the hoop-reared pigs beingfatter at market?

• Are niche markets available as alternativemarketing outlets?

• Will diets need to be tailored for cold or hotenvironments?

• Do all genetics of pigs work equally well?

Wean-to-finish

Hoop barns can be successfully used for wean-to-finish pig production. The slower turnover rate ofwean-to-finish production is a good fit with the lowerfixed costs of hoop barns. However, special attentionneeds to be given to the needs of the weaned pigs inthe hoop barn. During the summer in the Midwest,early-weaned pigs can be placed directly in beddedhoop barns. However, during fall, winter, and springthe early-weaned pigs need the protection of hoversand may need supplemental heat for the first fewweeks post-weaning. A variety of materials can beused to build hovers: plywood, plastic, or straw baleswith tarps. Special care must be taken when using

supplemental heat to minimize the risk of fire becauseof the bedding. Supplemental heat sources can be heatlamps, brooders, or radiant heaters.

Because large groups are common in hoop barns,the newly-weaned pigs should be carefully checked 3to 4 times per day. The large area in the hoop barncan be partially blocked off in the back of the hoopwith bales of bedding to make checking the pigseasier. Offer fresh feed 3 or 4 times per day on thefeeding platform. Some producers use feeding matsor boards to allow all pigs to eat simultaneously. Freshwater is critical. Provide temporary portable watertroughs for the pigs for the first 1 to 2 weeks. Makesure that each pig eats and drinks several times dailyfor the first 2 weeks. Gradually the pigs can be shiftedto self-feeders and automatic waterers. Althoughwean-to-finish has been successfully accomplished inhoop barns on a year-round basis, piglet growth forthe first 2 weeks postweaning during the coldermonths may be slower than in a hot nursery. Alsofiner bedding (for example, small grain straw orshredded cornstalks) may be preferable for the smallpigs. Some producers use ramps, bales, or moundedbedding to help the small pigs get onto the feedingplatform. Once the pigs are established and thebedding pack begins to compost giving off heat, thespecial measures can be withdrawn.

When hoops are used in wean-to-finish operations,producers will need to deal with issues related tofeeders and waterers.

Feeder design may be an issue for hoops whenused for wean-to-finish. Many feeders used in hoopsfor grow-finish pigs are not suitable for newlyweaned pigs. Issues include pigs getting trapped infeeder troughs, inability of small pigs to operate feeddelivery or agitation devices and height of the feederlip (4-6 inches recommended for newly weaned pigs).If feeders have lids, these need to be secured openuntil the pigs are big enough to open the lid for feedaccess.

Automatic water access may need to include theprovision of a step or platform to reach the drinkingtrough or water delivery mechanism. Low energy orno-energy freeze-proof drinkers typical of many hoopsused for grow-finish may not be suitable for newlyweaned pigs due to the difficulties in operating the lidand/or ball device in the drinking trough. In addition,the small pigs may not consume sufficient water tokeep the device ice-free. Thus, an electric or propane-fired heated drinker with a low-access height isrecommended until the pigs are big enough to accessthe regular drinkers.

23

SummaryThe full impact of new swine housing alternatives

such as hoop barns needs to be evaluated for short-and long-term effects. Producers considering a hoopbarn need to evaluate initial costs and operating costsfor each alternative. They also need to gather as muchinformation as possible about animal performancein different types of housing.

Among the major issues that a producerthinking about building a hoop barn must considerare the following:

• Managing winter ventilation is a crucialfactor in making a hoop barn successful.Hoop barns should not be closed so tightlythat moisture and warm air are trappedinside the structure.

• Hoop barns have lower fixed costs andhigher operating costs (for example:bedding, labor, animal efficiency) thanconfinement facilities.

• Hoop barns are versatile and can be used forother applications, such as machinerystorage, if not used to house pigs.

• If the tarp covering needs to be replacedbefore 10 years, tarp replacement costs mustbe added to cost calculations.

• Because hoop barns have a lower initial cost,producers can test their capability in swineproduction without a large investment.

• Producers who want to erect multiple hoopbarns for a swine operation may find thatthe volume of bedding will become a limitingfactor. The amount of bedding thataccumulates with more than four hoopbarns in one operation is substantial.

The example budget presented in Table 7 of thispublication suggests that a hoop barn can be acompetitive alternative building for pork production.However, producers should analyze their costs andcompare alternatives. Given similar costs, otherfactors may tip the building decision to a hoop barnor a confinement building.

Personal preference and perceived benefits of onestyle over another may sway a producer to choosewhich housing type is more appropriate for a specificsituation. For example, a producer who wants toexpand quickly may find a hoop barn to be the bestalternative, while another producer might concludethat the longer history and known attributes of aconfinement building are more appealing.Additionally, a fixed level of investment capital can

be spread over more pigs with the lower cost hoopbarn. This would allow for the return on a givenlevel of investment to be higher for the hoop barn.

References and ResourcesThose interested in additional information about thetopics discussed in this publication should consultthe following sources:

MWPS-33. Natural Ventilating Systems forLivestock Housing, first edition, 1989. MidWestPlan Service.

MWPS-32. Mechanical Ventilating Systems forLivestock Housing, first edition, 1990. MidWestPlan Service.

MWPS-34. Heating, Cooling and Tempering Airfor Livestock Housing, first edition, 1990.MidWest Plan Service.

MWPS-35. Farm and Home Concrete Handbook,1989. MidWest Plan Service.

Connor, M. L., L. Onisichuk, Q. Zhang, R. J.Parker, and J. I. Elliot. Alternative housingwith Canadian Biotech shelters and a reviewof some European concepts, 1994. Can. Soc.Ag. Eng. Paper 94-232, Saskatoon,Saskatchewan.

Edwards, W. and D. Smith. 2004 Iowa Farm CustomRate Survey. 2004. Iowa State University,Ames, IA.

Harmon, J. and H. Xin. Thermal Performance of aHoop Structure for Finishing Swine. 1996 SwineResearch Report, Iowa State University, Ames, IA.

Honeyman, M.S., J. D. Harmon, J.B. Kliebenstein,and T.L. Richard. 2001. Feasibility of hoopstructures for market swine in Iowa: Pigperformance, Pig environment, and Budgetanalysis. Applied Engineering in Agriculture17(6): 869–874.

Honeyman, M.S., F.W. Koenig, J.D. Harmon, D.C.Lay, Jr., J.B. Kliebenstein, T.L. Richard, andM.C. Brumm. 1999. Managing market pigs inhoop structures, PIH-138, Pork IndustryHandbook. Purdue Univ., W. Lafayette, IN.8 pp.

Honeyman, M.S. and J.D. Harmon. 2003.Performance of finishing pigs in hoop structuresand confinement during winter and summer.Journal of Animal Science. 81: 1663–1670.

Larson, M.E., M.S. Honeyman, and J.D. Harmon.2003. Performance and behavior of early-weaned pigs in hoop structures. AppliedEngineering in Agriculture. In press.

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domestic pigs. Livestock Production Science.65:71-79.

Beattie, V. E., N. Walker, and I. A. Sneddon. 1995.Effects of environmental enrichment andbehaviour and productivity of growing pigs.Animal Welfare. 4:207-220.

Klont, R. E., B. Hulsegge, A. H. Hoving-Bolink, M.A. Gerritzen, E. Kurt, H. A. Winkelman-Goedhart, I. C. de Jong, and R. W. Krannen.2001. Relationships between behavioral andmeat quality characteristics of pigs raisedunder barren and enriched housingconditions. Journal of Animal Science.79:2835-2843.

Swine mortality composting website: http:/www.abe. iastate.edu/PigsGone/index.htm

ReviewersMichael Boland, Professor of Ag Economics,

Kansas State UniversityTed Funk, Assistant Professor and Extension

Ag Engineer, University of IllinoisLarry Jacobson, Associate Professor and

Extension Ag Engineer, University ofMinnesota

Kevin Janni, Professor and ExtensionAg Engineer, University of Minnesota

John Lawrence, Professor and ExtensionAg Economist, Iowa State University

Donald Levis, Professor of Animal Science,The Ohio State University

Ronaldo Maghirang, Assistant Professor ofAg Engineering, Kansas State University

James Murphy, Professor and ExtensionAg Engineer, Kansas State University

Steve Pohl, Extension Ag Engineer, South DakotaState University

William Wilcke, Associate Professor and ExtensionAg Engineer, University of Minnesota

Yuanhui Zhang, Associate Professor ofAg Engineering, University of Illinois

Copyright © 2004, MidWest Plan Service,Iowa State University, Ames, Iowa 50011-3080 (515-294-4337)

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...And Justice for All.MidWest Plan Service publications are available to all potentialclientele without regard to race, color, sex, or national origin. Any-one who feels discriminated against should send a complaint within180 days to the secretary of Agriculture, Washington, DC 20250.We are an equal opportunity employer.

Lawrence, J. and A. Vontalge. LivestockEnterprise Budgets for Iowa—1996. 1996.Iowa State University, Ames, IA.

Lay, D.C. Jr., M.F. Haussmann, and M.J. Daniels.2000. Hoop housing for feeder pigs offers awelfare-friendly environment compared to anonbedded confinement system. Journal ofApplied Animal Welfare Science, 3(1): 33–48.

National Pork Producers Council. National SwineImprovement Federation Guidelines. 1988.Des Moines, IA.

Thomson Publishing Corporation. Boeckh 1997Agricultural Building Cost Guide. 1997. NewBerlin, WI.

Tiquia, S.M., T.L. Richard and M.S. Honeyman. 2002. Carbon, nutrient and mass loss duringcomposting. Nutrient Cycling in AgriculturalEcosystems. 62(1):15-24.

Tiquia S.M., T.L. Richard and M.S. Honeyman. 2000. Effect of windrow turning and seasonaltemperatures on composting of hog manurefrom hoop structures. Environ.Technol.20(9):1037-1046.

Larson, B., J. Kliebenstein, M. Honeyman, and A.Penner. Economics of Finishing Pigs in HoopStructures and Confinement: A SummerGroup under Different Space Restrictions.ASL-R1818, Animal Science Research Report2003. January 2003, Iowa State University.

Kliebenstein, J., B. Larson, M. Honeyman, and A.Penner. A Comparison of Production Costs,Returns and Profitability of Swine FinishingSystem. Working Paper #03006, EconomicsDepartment, Iowa State University, Ames,Iowa, March 2003.

Rosenvold, K., and H. J. Anderson. 2003. Factorsof significance for pork quality – a review.Meat Science. 64:219-237.

Beattie, V. E., N. E. O’Connell, and B. W. Moss. 2000.Influence of environmental enrichment on thebehaviour, performance and meat quality of

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