Gestation crates that confine pregnant sows throughout pregnancy prevent normal movement and behaviour, causing chronic welfare problems that have led to bans in several countries.
Complete immobilisation in gestation crates prevents turning around, lying comfortably, or performing any natural behaviour for months at a time. The welfare cost is extreme and well-documented through stress indicators and stereotype development. Group housing with appropriate feeding management achieves better welfare outcomes and is technically feasible at commercial scale as demonstrated by the EU transition.