The breed of chicken used in commercial meat production is one of the most significant determinants of welfare, with fast-growing breeds experiencing chronic health problems.
Fast-growing broiler breeds experience welfare problems inherent to their genetics: cardiovascular stress from rapid growth, skeletal malformation under bodyweight load, and chronic subclinical pain from gait problems. These breeds were selected entirely for growth rate and feed efficiency without welfare criteria. Switching to slower-growing breeds at commercial scale is technically feasible and has been demonstrated by multiple major producers. The welfare improvement is substantial and the cost premium modest.