Modern hyperprolific sow lines produce extremely large litters, creating welfare challenges for piglets that exceed the sow's nursing capacity and for sows themselves.
Hyperprolific sow genetics have created a welfare problem through overbreeding for productivity. Piglets born in overlarge litters face a competitive struggle for survival from birth - those that lose access to functional teats experience starvation in slow stages over several days. Crushing by the sow causes acute death but may involve prior suffering as piglets are unable to escape. Small piglets from large litters have weaker immune systems and greater susceptibility to disease throughout their lives. The sow herself experiences greater metabolic depletion nursing very large litters. This represents a welfare problem created by breeding choices that prioritize output metrics over the capacity of the biology to support them.