Farrowing crates confine sows in a space barely larger than their bodies for several weeks around birth. Their use is controversial and alternative systems are being developed.
Farrowing crates prevent natural nest-building behaviour that sows are strongly motivated to perform in the final 24-48 hours before birth. Inability to turn around, stretch fully, or attend to her piglets naturally creates chronic frustration and stress. Despite these welfare costs, crates are defended on piglet survival grounds. Well-managed pen farrowing systems achieve comparable piglet survival while preserving sow welfare. The trade-off is primarily a management challenge, not an inherent biological limitation.