The design of group gestation housing systems for sows significantly determines whether the welfare advantages over individual stalls are realised or undermined by aggression and competition.
Group gestation housing delivers its welfare promise only when designed and managed appropriately. Small static groups with adequate space, electronic feeding, and manipulable enrichment material provide dramatically better welfare than individual stalls. However, poorly designed systems with insufficient space, single-access feeding, or frequent re-mixing can create chronic aggression that causes injury, fear, and suppression of subordinate animals. The welfare improvement from moving to group housing is not automatic; it requires investment in appropriate design and management. The best group systems exceed stall welfare substantially; the worst represent a different form of failure.