A study conducted by the Prairie Swine Centre, which examined free space utilisation by sows in free access stalls, observed about 20 per cent of sows in the free access area at any given time.

About 95 per cent of the sows left their stalls at some point during gestation but about 40 percent spent less than two percent of their time outside the stalls and others spent 80 to 90 per cent out of the stalls.

Dr Harold Gonyou, a research scientist in animal behavior, says the sows that stayed outside tended to be the larger and older sows.

Dr Harold Gonyou-Prairie Swine Centre

What we want to do is create a management system where we have a fairly equal number of older and younger sows leaving the stalls and using the free access area.

Some of the advantages that we see from group housing relate to exercise and so a good group housing system will ensure that every animal gets to do a fair amount of exercise during the day so their muscle strength is good, their bone strength is good.

We found that will facilitate their giving birth and it will also be helpful just in terms of their general health and care of piglets.

What we have now is a system where it's disproportionate.

Some sows exercise a lot and some very little.

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.

Dr Gonyou says, while the free access stalls seem to have advantages, producers considering group housing need to know whether this system provides all of the advantages of group housing.