Maintaining stable social groups in commercial pig production reduces aggression, stress injuries and welfare costs. Regrouping practices significantly shape pig wellbeing throughout their lives.
Frequent regrouping is one of the most significant welfare challenges in commercial pig production. Each mixing event triggers a period of intense social stress, physical aggression and immune suppression. Animals that lose dominance contests experience chronic subordination stress, reduced feed access and increased vulnerability to disease. Stable social groups with consistent companions throughout their lives show markedly better welfare outcomes, including lower cortisol, fewer injuries and greater expression of positive social behaviours such as play and mutual grooming.