The scientific evidence on gestation crate impacts on sow welfare helped drive legislative change, offering lessons for evidence-based animal welfare policy.
Scientific evidence showed gestation crates cause muscle atrophy from inactivity, increased urinary tract infections, limb problems, and stereotypic behaviours indicating frustration. Sows unable to engage in nesting or rooting behaviours before farrowing show elevated stress hormones. The cumulative welfare impact on 100+ million sows globally before and during the phase-out period is immense.