There are still operations that limit feed, but the bulk of producers now provide their animals with an abundance of feed. Pens full of pigs that are all approaching market weight at the same time have space constraints that may limit access to food supplies. In non-sorted pens there is more room to manoeuvre because there are only a few fatsos in there at one time. Gonyou has conducted numerous studies on the subject in Canada and at the University of Illinois, where he worked before being hired by the swine centre in Saskatoon. A recent Kansas State University study confirms his findings.
Every farmer likes to go in and see a pen of very uniform animals.
Producers who are used to showing animals or taking them to auction know that a pen of uniform pigs is visually appealing. It's a procedure we don't need to be doing, but we spend time doing it. Gonyou said there are times when sorting is necessary. For instance, gestating sows have to be limit fed. But new feeding systems, such as the electronic sow feeder, could even eliminate the need to sort gestating sows.