How understanding and managing pig social behaviour during mixing events can significantly reduce injuries, stress, and welfare losses in commercial production.
Social stress from mixing is one of the most significant and avoidable welfare harms in commercial pig production. The pain and injury from fighting are direct welfare costs; the chronic stress of a low-ranking animal in an unstable hierarchy represents ongoing suffering. Production systems that prioritise logistical convenience over social stability — repeatedly remixing pigs at each production stage — create predictable aggression events. More stable group management, combined with environmental design that allows subordinate animals to avoid dominant ones, substantially reduces this welfare burden. The economic case for reducing mixing aggression is also clear: injuries require veterinary treatment, and fighting depresses growth rates. Transitioning to systems with stable groups throughout production requires planning but delivers both welfare and production benefits.