Switching from fast-growing to slower-growing broiler breeds dramatically reduces the health and welfare problems caused by extreme selection for growth rate, at the cost of increased production time and some additional resource use.
The welfare improvement from switching to slower-growing breeds is substantial and well-documented. The reduction in skeletal pain, cardiovascular disease, and metabolic disorders means that each bird lives a less painful life, even if the absolute duration of production is longer. For the individual bird, slower growth represents a dramatic quality-of-life improvement over the welfare burdens carried by fast-growing breeds.