Pigs are highly social animals whose welfare in group housing depends on group stability, space, and management of social hierarchies.
Group housing for sows and growing pigs provides social interaction essential for welfare but requires careful management of mixing events that trigger intense aggression. Injuries from fighting at mixing can be severe, including ear biting, flank wounds, and vulva biting. Management strategies reducing mixing including stable groups, adequate space, and individual feeding systems significantly reduce welfare harm. Anti-social behaviours including bullying and resource guarding indicate inadequate space or resources within groups. Successful group housing that supports positive social interaction represents significantly better welfare than solitary confinement in crates or stalls.