How to manage the welfare challenge of aggression when transitioning pigs from individual to group housing.
The transition from individual to group housing for pigs — driven by welfare legislation and consumer demand — creates its own welfare challenge through introduction aggression. When unfamiliar pigs are mixed, they establish social hierarchies through fighting, with weaker individuals suffering significant injuries. Managing this transition requires a systems approach: stable long-term groups rather than frequent mixing, adequate space to allow escape from aggressive encounters, multiple feeding stations to prevent resource guarding, and enrichment that redirects investigative and aggressive drives. The welfare goal is not just better housing but a genuinely better welfare outcome — which requires managing the social dynamics of the transition carefully.