Managing aggression in group-housed sow systems is the primary practical welfare challenge in the transition from gestation crates, requiring specific management expertise.
Aggression in group-housed sows is a genuine welfare challenge, but it is manageable rather than inevitable. The welfare harm of aggression — bite wounds, prolonged fighting, stress-induced pregnancy loss — is not inherent to group housing but reflects poorly designed or managed systems. Well-designed group housing with adequate space, stable group composition, individual feeding access, and appropriate enrichment achieves low aggression rates that represent genuinely better welfare than both gestation crate confinement and poorly managed group systems. The evidence that good group housing is achievable is demonstrated by farms worldwide that consistently maintain low aggression indicators.