Bar-biting in sows is a stereotypic behavior indicating chronic frustration — its prevalence in gestation stall systems reflects fundamental welfare failures.
Bar-biting is a visible welfare indicator with a clear causal story: sows confined in gestation stalls cannot turn around, express rooting behavior, or engage in meaningful social interaction. The highly motivated behavioral systems for exploration and foraging have no outlet, leading to the development of stereotypic behaviors as a coping mechanism. The prevalence of bar-biting in gestation stall systems is direct evidence that these systems cause chronic psychological suffering. The legal ban on extended gestation stall use in the EU represents genuine regulatory progress, but loopholes and poor enforcement mean many sows still experience this confinement. Consumer pressure for full group-housing systems, where sows can move freely and interact, is driving faster change in markets ahead of regulation.