Commercial pigs are typically weaned at 3-4 weeks — far earlier than the natural 12-17 weeks. Early weaning causes significant stress and has lasting effects on pig health and behaviour.
Weaning stress in pigs is one of the most well-documented welfare challenges in commercial pig farming. The combination of separation from the sow, social mixing with unfamiliar piglets, dietary transition from milk to solid food, and new environment creates a perfect storm of stressors. Cortisol spikes, immune suppression and gut barrier disruption follow. The resulting post-weaning diarrhoea creates a major justification for prophylactic antibiotic use — meaning that early weaning practices directly drive antibiotic resistance concerns alongside animal welfare problems. Higher-welfare systems with later weaning and enriched environments produce healthier piglets with lower antibiotic requirements, though the economics currently push in the opposite direction.