Aggressive behavior is a major welfare challenge in farmed pig production, with mixing of unfamiliar pigs triggering fighting that causes serious injuries, stress, and mortality in commercial systems.
Aggression in pig farming causes widespread suffering that is almost entirely a consequence of management practices. Wild pigs live in stable family groups and rarely fight seriously. Commercial operations disrupt this by mixing unfamiliar pigs and providing barren environments with nothing to investigate or manipulate. The resulting fighting causes skin wounds that become infected, lameness from hoof injuries, and the chronic stress of living in unstable social hierarchies. Tail biting - where pigs bite each other's tails - can escalate to cannibalism and is a welfare crisis in many systems, 'solved' through tail docking rather than addressing root causes.