Pigs establish clear social hierarchies within groups, and management that disrupts or ignores these relationships causes aggression and welfare harm.
Regrouping stress is a preventable welfare problem in pig farming. Maintaining stable groups from weaning to slaughter, minimising mixing events, and using short-term management techniques including temporary separation of attackers reduces injury and suffering. Where mixing is unavoidable, providing adequate space to escape, multiple feeding points, and appropriate distraction reduces fighting severity.