Pigs are highly social animals that benefit from group housing. Managing group dynamics to minimize aggression while allowing social expression is central to pig welfare improvement.
Pig social welfare is shaped by the fundamental tension between pigs strong hierarchy-establishing drives and the management practice of mixing unfamiliar animals at various production stages. Each mixing event triggers fighting that may last days, causing injury and chronic stress. The welfare-positive management approach minimizes mixing events through consistent group composition from early life, provides adequate space for subordinate animals to retreat, and offers sufficient enrichment to reduce redirected aggression. Stable social groups also deliver production benefits through reduced injury, better feed conversion, and improved immune function — aligning welfare and economic incentives. Policy requirements for minimum space and enrichment provision support these welfare outcomes.