Commercial piglets are weaned at 21-28 days, far earlier than natural weaning at 12-17 weeks, and the welfare implications of this early separation have driven welfare certification requirements for later weaning.
Commercial pig weaning age creates welfare harm through abruptness and earliness relative to biological norms. At 21-28 days, piglets are developmentally immature and immune systems are incompletely developed. The combined stress of maternal separation, diet change, and social disruption from mixing creates acute welfare harm that produces the post-weaning diarrhea and growth checks common in commercial systems. Later weaning allows more complete immune development and social security. Welfare certification standards requiring later weaning ages reflect the scientific evidence that earlier commercial weaning is a welfare compromise driven by production efficiency rather than animal needs.