Commercial piglets are weaned at 21 days or less, far earlier than their natural weaning age of 12-17 weeks. Earlier weaning causes welfare problems for both sows and piglets.
Early weaning at three weeks causes acute distress in piglets who are developmentally prepared for gradual weaning over months, not abrupt separation. Piglets removed from sows at this age show vocalization, reduced feeding, and belly nosing — a redirected suckling behavior performed on pen-mates that indicates the suckling motivation remains strong. Post-weaning diarrhea from gut immaturity causes suffering and mortality in young pigs. Extending weaning to 28 days or beyond reduces these welfare problems measurably. The economic pressure toward early weaning comes from wanting sows to return to estrus quickly for the next pregnancy. Longer weaning age requires more sow housing but delivers welfare improvements for both generations.