Commercial weaning of piglets at 3-4 weeks of age — far earlier than natural weaning at 3-4 months — is a major welfare challenge. The combined stressors of maternal separation, diet change, and social mixing cause significant short-term suffering and long-term health impacts.
Early weaning inflicts multiple simultaneous stressors on developing piglets: loss of the mother and her thermoregulatory support, loss of familiar social companions, unfamiliar social mixing with aggression, and a gut-disturbing diet transition. The resulting stress response suppresses immune function during a period of maximum vulnerability, increasing disease risk. Piglets separated at younger ages show higher cortisol, more stereotypic behaviour, and poorer welfare outcomes than those weaned later. While economic pressures drive early weaning — sows can be rebred sooner — the welfare case for extended weaning ages is compelling. Some premium welfare schemes mandate minimum weaning ages of 28 or 35 days as a baseline welfare standard.