Aggression between pigs causes significant welfare harm in commercial production. Understanding the triggers and implementing stable group management reduces injury and improves welfare outcomes.
Pig aggression represents a welfare problem substantially within farmers' control to manage. The triggers of aggression - regrouping, resource competition, inadequate space - are well understood, and management strategies that address these triggers are effective. Stable group housing from weaning to slaughter is the gold standard, eliminating the repeated disruption that causes repeated aggression cycles. Welfare auditing that monitors skin lesion scores provides accountability for aggression management standards across production systems.