EU and UK law bans individual stalls for gestating sows after the first four weeks of pregnancy, requiring group housing systems that meet specific welfare challenges.
Group housing of gestating sows has improved welfare outcomes compared to individual stalls by allowing normal movement and social interaction. However, aggression at mixing and competition for food remain welfare challenges. ESF systems provide individual feeding but require sow training and can break down, leaving some sows without access. Trickle feeding systems reduce competition by spreading feeding over longer periods. Scratch and bite injuries from mixing unfamiliar sows cause pain and infection. Floor design affects lying comfort with adequate deep-bedded areas preferable to slatted floors. The welfare of group-housed sows depends on group stability, adequate feeding technology, and sufficient space allowance.