Breeding All mammalian life starts with a male and a female, and it's no different with pigs. Male pigs are largely solitary, although they sometimes form bachelor groups in late summer, the non-breeding season for wild pigs. Males and females only merge during rutting season, a time when the well-defined group structures of pigs become less stable. In Truebridge barns, the resident boars have private pens usually near the breeding area. Boars are used to stimulate sexual receptivity in sows, but the sows are typically artificially inseminated.		(before remodel) Conventional Breeding Stalls       (after remodel) Large Breeding Pen with Free Access Stalls         A boar interacting with a neighboring sow.   A hormone-fueled altercation in the breeding pen.     The breeding pen has an open area for the sows to interact.   Free access pens let sows get away from each other.         The pen design lets the sows let themselves in and out.   The sows choose pens near their friends and relax.
A female pig's estrus cycle is 21 days, which means that every 21 days there is a 2-4 day window during which she ovulates. If she is bred during this period, she usually becomes pregnant. Sows in heat experience a surge of hormones, which often makes them more aggressive toward each other. So, Truebridge breeding pens have a two-part layout. Most of the pen consists of a large, bedded, communal area, where the sows can walk around and mingle. Along each side of this large central pen is a line of smaller individual pens called free-access pens. These mini pens allow sows to get a little privacy and/or security from other more rowdy pen-mates. On a commercial farm, sows are bred in breeding stalls that are typically 2 feet wide by 7 feet long. They can stand up, but not turn around, and once they are bred, they are moved to a gestation stall of the same dimensions, in a different section of the barn. Free access pens are different, because the sow herself chooses if she wants to be inside one of the mini pens or go out into the larger pen. Upon entering, she presses against a panel with her snout, which causes a counter-levered gate to swing shut behind her. This blocks other sows from entering and bothering her. When the sow backs up to exit the pen, her rump bumps gently against the rear gate, causing it to swing up and out of her way. It's a bit like the pig version of a Tokyo capsule hotel. The sows also eat in these free access pens, which negates any competition or fighting at the trough. Usually, sows that are friends will enter neighboring free access pens together, so they can eat and rest beside each other, while isolating themselves from the rest of the group. Some sows spend a fair amount of time in the stalls because they are more timid and feel more relaxed there. Just as people tend to do, pigs choose a favorite spot and always return to claim it. When the farmers are ready to breed a group of sows, they can temporarily lock the rear gates of the free access pens (around breakfast time, when everyone's already come inside to eat). Then the boars get to go for a stroll around the barn. Females show signs that they are in heat and ready to be bred much stronger in the presence of a boar. So the boars are trained to walk in the aisle in front of the sows and the staff observe which sows show signs of heat and can be bred. This lets them get the job done quickly without needing to disrupt the sows. Each sow has a microchip inside her ear tag that identifies her. The farmer can scan her tag with a handheld computer and see all her data, such as when her last group of piglets were weaned, when she was last bred, or how recently she's been given a pregnancy test. This helps the farmer figure out who needs what when all the sows are in a big pen together. For convenience sake, the farmers also use brightly colored non-toxic paint to mark sows' backs when they breed them. That's why the sows living in the breeding pens look so colorful.