How selection for large litter sizes in commercial pig breeding has created welfare challenges for piglets and sows.
Litter size selection in commercial pig breeding represents a case where production optimization has created welfare problems at both individual and population levels. When litters exceed the sow teat count, runts face starvation without intervention, and management responses including cross-fostering and milk supplementation create additional handling stress. Large litters also tax sow nutrition severely. Progressive breeding programs are beginning to include piglet vitality, uniformity, and survival as selection criteria alongside litter size, shifting toward welfare-conscious genetic selection.