Pigs are highly social animals with complex group hierarchies. Understanding and managing social dynamics improves welfare and reduces aggression-related injuries.
Social welfare in pigs requires stable, appropriately sized groups with adequate space and resources. The common practice of repeatedly mixing pigs from different litters and farms creates constant social disruption and fighting. Each mixing event involves acute suffering from aggression, with wounds that can become infected. Stable lifelong social groups - possible in some outdoor and deep straw systems - show much better social welfare. Resource distribution that allows all pigs access to feed, water, and resting areas without competition reduces aggression and improves welfare throughout the group.