Politics can cause strange things to happen, as is evident by the “Terminator” being elected governor of California. Politics also can affect issues in the pork industry, regardless of the possible production or economic impact.

Group housing for sows may not be the ideal system for the pork industry to use, but such decisions aren’t always left up to the industry.

“The jury is still out on whether pens or stalls are better for the sow’s welfare,” says Barbara Straw, DVM, Michigan State University. “The question may not be decided by science, it may be decided by the voters – like it was in Florida.”

Each system has its pros and cons, says Straw. With stalls you can feed the sows individually, there is less lameness, less fighting, less tail and vulva biting. The only apparent con to stalls is the sow’s limited mobility. But Straw points out that it’s much easier to monitor physical traits than psychological traits, leaving some question marks about welfare issues.

There are many production challenges that need to be addressed for group-housing. Not being able to feed sows individually is a big negative surrounding group-housed sows, that and injuries caused by competing for food.

“The challenge is to make sure each sow gets the right amount of feed,” says Don Levis, Ohio State University Extension swine specialist. “If a sow doesn’t get food for a couple of days, it can develop reproductive problems.”

“A disadvantage of group-housing is that there are wide variances in body condition. Every pen has a couple of really thin sows and some dominant sows get too fat,” says Levis. “Probably the biggest disadvantage is there’s too much fighting at times.”

Feeding every three days can help body condition uniformity within a pen of sows, says Levis. On feeding day, the sows are allowed to feed for two to 12 hours, but then they’re not fed for another two days. Levis is not sure why that improves body condition uniformity, but he theorizes that thinner sows have an opportunity to increase the amount of feed consumed after the more aggressive sows have gotten their fill. There is still some fighting, especially on feeding day, but it is no more or less than other group-housed system, he adds.

Feeding sows every three days may help uniformity issues, but if animal welfare drives sow housing, feeding every three days isn’t likely to be an acceptable idea. Even with daily feedings, group housing may not be the best option for animal welfare. Depending on how much and the type of space there is in the pens, the sows may not have room to get away from a fight, making welfare worse, says Levis.

Space requirements vary greatly, but there is usually about 16 to 18 square feet per sow in a totally slatted facility, 20 to 24-square-feet in a solid-floor confinement building, and up to 25 square feet in a hoop building. In pen environments, groups of 15 to 20 sows are common, and in hoop buildings that number can jump to 50 sows. Ideally, you would have one feeder hole per sow, but Levis says that is too expensive to ever happen. He has seen arrangements with 28 holes (14 holes per feeder) for a group of 50 sows and the sows were still in good shape. When each sow does not have its own feeder hole, the duration required for feeding increases.

In group systems it’s important to pay attention to your sows. Straw says you can expect to have more injuries in the pens. Also lame sows tend to hang back and not get all the feed they need.

“It’s much harder to check sows for heat and pregnancy in pens, which results in lower farrowing rates,” says Straw. “You need to account for lower farrowing rates by overstocking the pen before breeding, and then removing animals that didn’t get bred. The other option is to leave pens understocked once you’ve removed sows that didn’t get bred.”

If you don’t want to leave the pen understocked, you can mix new sows into the group, but that causes fighting to increase.

“Ideally, you need to establish the group and leave the sows together. Data shows that mixing sows lowers litter size and farrowing rates,” says Levis. “However, a lot of times you need to mix sows over a two week period, because production schedules don’t allow you to establish a static group.”

While there’s currently no economic advantage to group-housed sows, according to Levis, additional research needs to be conducted to determine the best systems to manage and to feed group-housed sows, in case regulations do someday outlaw gestation crates.

For starters, group the sows by body condition. Even after doing that, the animals will establish a pecking order, with some sows dominating other sows.

Straw has worked with a system that drops feed six to eight times a day, but in very small amounts. For example, if the sows are suppose to get 4 pounds of feed a day, only one half of a pound of feed per sow would drop each of the eight times.

“This system reduces fighting and the excitement that goes on at feeding time,” says Straw. “The frequent feed drops turn feeding time into a non-event.

This system reduces competition between sows, but requires a timer on the feeder and solid or partially slatted floors, so the feed has a logical place to land.

There are other new systems cropping up. Some systems have feeding stalls that are about 6 feet long. The sows go into the stalls to eat and are let out when they’re finished. Levis says many of the sows will hang around in the stalls, which might suggest that stalls are not as bad for animal welfare as some might think.

There are several variations on the feeding stalls, including self-locking models that keep dominant sows from stealing food from more submissive sows.

“If I had my choice of all the systems now used for group-housing, I’d make sure each sow was individually fed in a stall and then turned loose,” says Levis.

Electronic sow feeders are another technology that has potential. However, they are expensive, require labor for training sows to use the feeder, need to be monitored to ensure sows are eating, and require maintenance. He believes electronic feeders have some potential, but they will require electronic ear tags and modified designs.

Economics will play a major role in determining which, if any, system becomes widely used. Straw thinks that hand feeding is probably the cheapest method, but feed-drop systems are close in terms of costs, and they allow much more precision. Economic comparisons among different types of group-housing systems are difficult.

“I don’t know if anyone has studied the economics of one system over another,” says Levis. “We also need to remember that just because you put in a more expensive system, that doesn’t necessarily mean you get better performance.”

Straw points out that the costs between building a new pen-housing system and retro-fitting an existing system also need to be considered.

While the time of housing sows in groups may not be here yet, it’s a good idea to be looking for practical and economical options. You never know what voters and/or politicians will do.