Farrowing crates prevent sow movement for weeks around birth; free-farrowing systems allow natural behaviors while managing piglet crushing risk with welfare benefit to both sow and piglets.
Farrowing crates impose extreme confinement on sows during one of the most behaviorally significant periods of their lives. Nest building is a strong behavioral imperative in sows before farrowing, and crate confinement prevents this entirely, causing significant frustration and stress. Free-farrowing systems including 'PigSAFE' and similar designs have demonstrated that piglet mortality can be maintained at acceptable levels while restoring freedom of movement to sows. The welfare benefit to the sow - weeks of freedom versus weeks of confinement - is substantial and increasingly recognized in welfare legislation.