Pig Sow Housing After Farrowing: Welfare in the Post-Weaning Period

The period after weaning is a welfare-critical time for sows returning to group housing. Managing this transition reduces aggression and supports rapid return to reproductive health.

Key Facts

Sows are typically weaned from their piglets at 21-28 days in commercial production — earlier than the natural weaning age of 8-12 weeks
After weaning, sows return to group gestation housing where mixing with unfamiliar animals causes hierarchy-establishing aggression
The 5-7 days after weaning represent a peak risk period for sow injury from fighting as dominance hierarchies are re-established in newly mixed groups
Oestrus returns in sows 4-7 days after weaning — the timing of mixing and management during this period affects both welfare and reproductive performance
Providing ample feeding space, hiding places, and temporary individual feeding stalls at re-introduction significantly reduces fighting severity
Stable group composition — returning sows to their previous group mates rather than mixing at each cycle — is the most effective welfare intervention for post-weaning aggression
Some farms use computer-controlled individual feeding stations in loose housing that allow sows to access food without competition from dominant animals

Welfare Considerations

The post-weaning period for sows is a welfare pinch point that receives less attention than farrowing welfare despite causing significant suffering. Mixing stress in sows — the aggression associated with re-establishing dominance hierarchies in newly formed or reformed groups — causes injuries including ear and skin wounds, vulva biting, and lameness. The welfare cost is compounded by the stress of weaning itself, which disrupts a hormonally mediated relationship between sow and piglets. Stable group management and appropriate housing design can substantially reduce mixing-related aggression, but these require investment in farm infrastructure and management discipline that is not universal across commercial pig farms.

What You Can Do

Advocate for stable sow group composition across production cycles as a mandatory welfare standard in pig farm assurance schemes
Support investment in computer-controlled feeding systems that eliminate food competition stress in group-housed sows
Choose pork from farms with documented sow welfare standards that address post-weaning management as well as farrowing conditions
Engage with the pig industry on the economic case for reducing post-weaning aggression — injury costs and reproductive failure from stress both have commercial consequences
Donate to pig welfare research into aggression management in group-housing systems
Push for veterinary herd health plans to include post-weaning sow welfare monitoring as a standard component
Raise awareness that sow welfare extends throughout the production cycle — farrowing is the most visible welfare concern, but post-weaning management is equally important