Researchers with the Prairie Swine Centre (PSC) at Saskatoon, Saskatchewan, Canada are scratching their heads these days trying to figure out this conundrum. Why does it seem that when given the choice, some gestating sows will spend the majority of their time in stalls, while others prefer to be in the free access area most of the time.

A study conducted by the Prairie Swine Centre examined free space utilization by sows in free-access stalls. The study found about 20% of sows in the free-access area at any given time. About 95% of the sows left their stalls at some point during gestation, but about 40% spent less than 2% of their time outside the stalls, while others spent 80-90% of their time out of the stalls.

Harold Gonyou, PSC researcher in animal behavior, reports the sows that stayed outside tended to be the large and older sows.

Gonyou says more work will be done to try and determine why some sows prefer more exercise than others. “We’re looking at this question of whether or not the sows are staying in because it’s a social threat to leave the stall, or whether it is a question of is it more comfortable in the exercise area than in the stall.

“We’re going to be doing some more work where we manipulate the comfort level both within the stall and outside and also manipulate the social combinations that we put together in a group to see if we can better manage and get a more even distribution of sows leaving the stalls and exercising,” Gonyou says.

Free-access stalls seem to have advantages, but producers considering group sow housing need to know whether this system provides all the advantages of group housing, he explains.