Commercial pigs are weaned at 3 to 4 weeks of age, far earlier than the natural weaning age of 12 to 17 weeks, causing documented stress and welfare harm to both piglets and sows.
Early weaning is a major acute welfare event in pig production. Piglets lose maternal contact, familiar social companions, and their primary food source simultaneously, triggering a stress cascade measurable through behavior, cortisol, and immune suppression. Sows show distress behaviors including vocalization and pen investigation after piglet removal. Extending weaning age reduces these harms but reduces sow productivity in commercial systems, creating an economic pressure against welfare improvement.