Early weaning of piglets at 3-4 weeks is standard in intensive systems but causes stress for both sows and piglets compared to natural weaning at 3 months.
Weaning is one of the most stressful events in a commercial piglet's life. Abrupt removal from the mother simultaneously removes the source of nutrition, warmth, and social security, while the mixing of litters at weaning introduces aggression. Early-weaned piglets commonly perform belly-nosing on pen-mates — a redirected suckling behaviour — and show elevated cortisol for days after separation. Extending weaning age even modestly has measurable welfare benefits for both sow and piglets.