Farrowing crates confine sows during and after birth, preventing crushing of piglets but severely restricting maternal behavior. Welfare science and alternative systems are changing industry practice.
Farrowing crates represent a welfare trade-off that pig farming has increasingly recognized as unnecessary with appropriate system design. Sows in farrowing crates cannot turn around, nest-build, or fully express maternal behavior. The nesting motivation is so strong that crate-confined sows perform vacuum nest-building behaviors - the movement patterns of building without any material - in the hours before farrowing. This is clear evidence of behavioral frustration. Well-designed free-farrowing systems with appropriate nest boxes, sloped sides, and temperature-controlled creep areas achieve piglet mortality rates comparable to crates while allowing full expression of maternal behavior.