The EU and UK ban on sow stalls (individual gestation crates) for most of pregnancy transformed pig farming. Group housing provides welfare benefits but introduces new management challenges requiring skilled stockpersonship.
The transition from sow stalls to group housing represented a major welfare advance, eliminating the most obvious welfare harms of complete movement restriction and forced posture. However, group housing introduces new welfare challenges that require skilled management. Aggression when groups are mixed or disrupted causes injuries including vulvar biting, back lesions, and lameness. Management strategies including stable group formation, sufficient space per sow, appropriate feeding system design, and minimising group changes significantly reduce aggression. Research on sow preferences consistently shows that given choice, sows prefer group housing with enrichment over individual crates, indicating that group housing better meets their behavioural needs. The ongoing welfare gap in commercial group housing relates to enrichment provision and space allowance: minimum legal space requirements may be insufficient for stable low-aggression social dynamics.