Birth weight variation within pig litters creates welfare disparities with significant consequences for low-birth-weight piglets across their production lives.
Birth weight variation within pig litters creates a cascade of welfare disadvantages for smaller piglets that compound throughout the production cycle. Low birth weight piglets compete unsuccessfully for teats, receive inadequate colostrum, grow more slowly, and face higher disease burden. The genetic selection that produces hyperprolific sows has exacerbated this problem by increasing both litter size and within-litter variation. The welfare case for revisiting hyperprolific breeding targets is strong - maximizing litter size at the expense of litter quality creates welfare harm for a predictable subset of each litter across millions of births annually. Management interventions including colostrum supplementation and cross-fostering provide partial mitigation.