Transitioning pigs from individual to group housing improves welfare but introduces aggression challenges. Understanding and managing the transition reduces welfare compromise.
Group housing transition represents a genuine welfare improvement over gestation crates, but the transition is not welfare-neutral. The social upheaval of group formation — particularly when sows are mixed at service or during early pregnancy — causes significant aggression that can result in injuries, spontaneous abortion, and death. The welfare benefits of group housing materialise over time as hierarchies stabilise and sows express normal social behaviour, but the transition costs must be managed carefully. Best practice involves mixing at weaning before the aggression-prone service period, providing adequate space to allow avoidance, installing feeding systems that prevent resource competition, and monitoring for injuries during the high-risk period after mixing. Farmers transitioning to group systems need practical support and training to optimise outcomes.