Selection for hyperprolific sows producing very large litters creates welfare trade-offs between sow health and piglet viability that have significant welfare implications at industry scale.
Hyperprolific sow welfare involves a genuine welfare trade-off between the aggregate welfare mathematics of more piglets per sow and the individual welfare of sows and their piglets. Large litters with multiple low-birth-weight piglets experience higher mortality from crushing, competition and hypoglycemia. Sows nursing large litters experience significant metabolic stress and body condition loss. The industry assumption that more piglets per sow is inherently positive from a welfare standpoint ignores the welfare costs distributed across sow health and piglet survival. Selection for optimized litter sizes that balance sow welfare, piglet viability and litter size rather than maximizing litter size alone would better serve welfare outcomes.