The two primary benefits of gestation stalls are:

• They remove the social stress of group-housed sows. Pigs are social animals and will always establish a hierarchy or pecking order. That process is not pretty in group-housed sows as there is often serious fighting when groups are formed and intermittent fighting at all times as the “order” is enforced. That fighting and stress leads to injuries such as cuts, scratches, torn ears and, in some cases, broken bones. These are prevented by stalls.

• They allow sows to be managed as individuals. Thin sows can be given more feed, without that extra feed being stolen by a larger boss sow. Meanwhile, heavy sows can be fed less to maintain body condition more conducive to productivity and longevity. Health challenges are easier to observe and treat.

It’s no coincidence that the productivity in litters/sow increased significantly as more and more U.S. sows were moved to stalls beginning in the 1990s. Of course, stalls were not the only factor in this improvement, as artificial insemination, more accurate pregnancy detection and other practices all played a role. But indoor-housed, stalled sows were a major driver.

All systems have trade-offs. The obvious negative one for sow stalls is that sows are denied many of their natural behaviors. As noted above, some of those behaviors can be destructive. But they are natural and that seems to be the primary concern of groups like the Humane Society of the U.S. It now seems to be the primary concern of McDonald’s as well.

Can pork producers meet these demands? Yes. Will there be a cost? Yes. There are two viable alternatives to stalls: small groups of, generally, 6-12 sows and large groups of as many as 100 sows. Both allow sows slightly more individual space and the freedom to turn around and interact with other animals.

Small-group systems usually use a feed-delivery system that meters feed to individual feeding stations at a rate the sow can eat immediately, thus providing no loss to a weaker, more timid sow and no gain to a boss sow.

Large-group systems usually use electronic feeding stations, which read ear tags and allow sows only so much feed during a specific time period, thus regulating body condition. Productivity levels close to those of stall systems can be achieved.

The tradeoffs are more sow injuries, higher feed costs (mobility takes energy), higher labor costs, and very likely more injuries to workers. Those will not be free and, in the long run, consumers pay all costs. That last one always seems hard to remember.