Group housing of sows in dry sow housing requires careful management of aggression - research into stable group formation and mixing protocols significantly improves welfare outcomes.
Sow group housing aggression welfare has been substantially addressed by research into management protocols that minimise mixing injuries. The welfare improvement from eliminating gestation crate confinement is significant, but improperly managed group housing can create different welfare harms through aggression. The research evidence provides practical guidance: stable groups, delayed mixing after service, multiple feeding points and appropriate space allowances combine to reduce aggression welfare costs. Training stockpeople in aggression monitoring and intervention enables rapid response when problems arise. Welfare certification schemes should specify evidence-based aggression management protocols rather than merely requiring group housing.