Group Housing Systems for Pregnant Sows: Welfare Evidence

Group housing of pregnant sows — replacing individual gestation stalls — is now required across much of Europe and increasingly adopted globally. The welfare evidence strongly supports well-managed group systems.

Key Facts

Gestation stalls — individual metal crates too small to turn around — were the dominant sow housing system for decades.
EU legislation banned new gestation stall construction from 2003 and required full phase-out by 2013.
The US, Canada, Australia, and major food companies have committed to gestation stall phase-out through supply chain pressure.
Well-managed group systems produce sows with lower cortisol, less stereotypic behaviour, and better welfare outcomes.
Electronic sow feeders (ESF) allow individual feed management in large groups without competitive access problems.
Aggression at group formation remains a welfare challenge requiring careful mixing management and appropriate space.

Welfare Considerations

The welfare evidence supporting group housing over gestation stalls is robust. Sows in individual stalls cannot turn around, perform rooting, maintain normal posture, or engage in social behaviour — the confinement causes chronic frustration measurable through stereotypic bar-biting, elevated stress hormones, and musculoskeletal deterioration from inability to stand and move normally. Group housed sows show significantly lower rates of stereotypic behaviour, better musculoskeletal health, and more natural time budgets. The welfare challenge of group housing — aggression at mixing — is manageable through good practice: electronic sow feeders eliminate competitive feeding stress; adequate floor space (2.25 m³ per sow minimum in EU systems) allows avoidance; and stable group composition after initial mixing reduces ongoing aggression. Bedded loose-housing systems with straw provide rooting opportunity and significantly improve welfare outcomes over concrete-slatted group systems. The transition from stalls to well-managed group housing represents one of the most significant farm animal welfare improvements in recent decades.

What You Can Do

Choose pork products certified as gestation-stall-free, confirming sows are group-housed during pregnancy.
Advocate for complete gestation stall bans in countries that still permit them, including the US and Canada.
Ask food companies about their sow welfare commitments and gestation stall phase-out timelines in their supply chains.
Support welfare organisations campaigning for global gestation stall prohibition through international trade standards.
Learn about sow welfare science to engage effectively with industry and policy debates about housing system reform.