As the debate about group sow housing versus individual stalls continues, new research is uncovering which systems work best for both the animals and the people who care for them.

“For now we’re not going to move completely to group housing or completely away from individual stalls,” says Sam Baidoo, University of Minnesota assistant professor of swine nutrition and management. “It’s important to have a transition or combination of the two systems, so we can protect embryos during the critical development stages of pregnancy.”

To gain the best of both worlds, Baidoo says it makes sense to use individual stalls to ensure pregnancy — for a period following breeding — and then move sows into group housing once they are confirmed pregnant. For example, at the University of Minnesota’s Southern Research and OutreachCenter near Waseca, Minn., sows are bred and inseminated in crates before being moved within one week into the group-housing system.

Management takes priority

Group housing demands attentive management from start to finish, adds Pablo Moreno, DVM, with Murphy-Brown in Oklahoma. “Train your people about the ways a sow behaves and help them identify problems before they get worse. Observation is the key.”

Realize that sows will fight when they are mixed together in group housing. That fighting period will often extend for 48 to 72 hours after being mixed. Overall, your goal is to minimize stress and injury associated with the group forming its social hierarchy, notes James McKean, DVM, with IowaStateUniversity.

The shape of the group-housing pen can affect aggression duration and intensity. Research shows that circular pens cause higher aggression levels than square or rectangular pens. Also, a solid barrier within the pen reduces the total number of aggressive interactions during a 12-hour period after mixing sows.  To further control aggression, Moreno recommends providing 30 square feet per sow in group housing, along with one nipple waterer per 15 sows.

While some producers contend that the time of day when you mix sows can limit aggression, McKean urges caution. “If you mix sows after sunset, aggressive interactions can decrease over the short-term, but aggression levels the next morning will be the same as if pigs are mixed during daylight.”

Also, don’t expect chemicals to ease the tension. Anti-aggression drugs or sedatives appear to reduce fighting at first, but aggression rebounds to levels seen in untreated animals when the chemical wears off.  Even a boar’s presence is minimally effective at reducing fighting and scratches, according to some research, McKean notes.

To minimize aggression and animal stress, Baidoo does not recommend a dynamic system where new animals come in at various times. “I prefer the stable system where you have one group, and that group moves together,” he says.

Regarding herd health, group housing is no more likely to pose major disease outbreaks than current production systems, McKean adds. He points out that swine dysentery and Salmonella are orally transmitted and may occur in group-housing situations, but again, management is critical. 

“Learn to recognize unhealthy animals and sows that are unable to compete,” he says. “Signs of trouble include a thin body condition, excessive lesions and bite marks on a sow’s skin, and claw injuries. You will likely need to remove these animals to an injury pen and provide treatment or supplemental feed before the sows can return to the group-housing pen.”

Understanding feed needs

Since electronic feeders are often used in group-housing systems, you can achieve precise feeding for each sow.  “Feeding is extremely accurate, and the group sows on our research farm are in better overall condition than the sows in individual pens,” Baidoo says. He notes that the electronic-feeding systems make it easy to identify animals that are sick or off-feed.

In these systems, a gate closes behind a sow as she enters the feeding area and the computer reads her tag. If she has already eaten, no feed will drop and the gate will open again to let the sow exit. If a sow needs to eat, feed will drop and the gate will remain shut until the sow is done.

The system does require some training time. It may take two or three days for a sow to adapt to the feeding practice. While the Minnesota researchers have never had a problem with the feeding system being unable to read the tags, sometimes tags will get lost — mostly due to fighting. “That’s why you need to check the records regularly. Workers have to know the sows, and they must read the computer printout every day,” Baidoo says. He points to a hand-held data logger, which is compatible with PigChamp, as a tool to help employees monitor data.

During gestation, the feeding objective is to get sows into the proper body condition for farrowing, as well as to maximize future reproductive performance and meet daily nutrient requirements at the lowest cost possible. Variations in feed drops, however, can prevent you from reaching those goals no matter what kind of housing system you have, says Joel DeRouchey, Kansas State University Extension swine specialist.

“You have a lot of things on your mind every day, and you’re probably not thinking about whether the feeder that’s set for 5 pounds is actually dropping 5 pounds. As feed drops get bent to a 75- or 60-degree angle instead of a 90-degree angle, they may not be dropping as much feed as you expect,” he points out.

What about feeding frequency? Some people claim that feeding six times a day in a group-housing system rather than two times a day results in improved animal care and reproduction. DeRouchey says his research review shows that increasing the feeding frequency does not appear to have much impact — good or bad — on the performance or well-being of group-housed gilts and sows.

“However, feeding six times a day did result in a small but significant reduction in skin and vulva lesions, and structural problem scores,” he notes. 

In the end, there are many factors to consider as you re-evaluate your gestation-sow housing. “As times change, the type of system you select today should meet the needs of your sows, you and your employees, as well as the consumers. It needs to address animal welfare, high biological performance and an acceptable financial return,” Baidoo concludes.

That may require making the transition to a different housing system or revising the one you now have in place.