According to a special article featured in USDA's Livestock, Dairy and Poultry report, in recent years, a growing number of major U.S. companies that demand and supply pork products have adopted strategies that explicitly move away from direct or indirect use of gestation crates in pork production.
McDonald’s Corp.—a major buyer of pork products—and thus an indirect user of gestation crates—recently announced that it would require its pork suppliers to submit plans by May 2012 that transition suppliers’ production facilities from use of gestation crates, to group sow housing. McDonald’s thus joins other major U.S. buyers of pork products1 along with major U.S and Canadian pork-producing companies, in adopting business models that incorporate group sow housing in pork production.2
Pork users and pork producers appear to be making this move in response to a developing public perception that crating sows during gestation is detrimental to the welfare of the animal.
The Current U.S. Hog Production System: Gestation Crates
For the last 30 years, typical U.S. hog production has employed individual crates to house pregnant females during gestation.3 The typical gestation crate measures 7 feet by 2 feet, or 14 square feet, and was adopted by the industry to overcome innate hierarchical swine behavior.
Female swine, in particular, tend toward aggressive behavior to establish dominance when they are housed in groups. This means that freely moving pregnant swine tend to fight until dominance is established. Such aggression can cause serious injury to less-dominant females and to unborn piglets. When the females are crated, aggression and threat of injury are minimized. Gestation crates also facilitate individualized animal care, feeding, and monitoring.
The downside of gestation crates is the severe constraint on movement that the 14- square-foot crate imposes. While the crate affords the pregnant female some limited side-to-side and back-and-forth movement, it totally prevents the animal from turning itself around. The animal welfare questions that are raised by the movement limitations of gestation crates have motivated the industry to adopt a different means of pork production that allows the pregnant animal freedom of movement.
Group Sow Housing as an Alternative to Gestation Crates
A production model based on group sow housing places pregnant swine in open pens that allow them free movement. An accurate description of a “typical” group sow housing barn is elusive because no single type has yet evolved in the United States. Consequently, there is wide variation in design characteristics of existing grouped housing units.
For example, the number of animals grouped in one pen can vary anywhere from 5 animals to more than 100, depending on per-animal space allocations. The groups themselves can be “static,” meaning that all the animals in a pen enter it together when the group is formed, or “dynamic,” meaning that animals enter and exit the group.