Fast-growing broiler breeds suffer from breast muscle myopathies — white striping, woody breast, and spaghetti meat — that indicate welfare problems caused by extreme muscle growth rates.
Breast myopathies in broilers are welfare indicators that are literally visible in the product: the white striping and woody texture that consumers notice in supermarket chicken is evidence of muscle pathology caused by growth rates that exceed the capacity of blood supply development. The tissue ischemia and degeneration that produces white striping represents ongoing physiological harm to individual birds throughout their lives — a chronic welfare cost that is embedded in the breeding program itself. Birds with severe woody breast show behavioral changes consistent with reduced comfort and mobility. These conditions are directly and causally linked to growth rate: switching to slower-growing breeds virtually eliminates the problem. The Better Chicken Commitment and similar corporate pledges to adopt slower-growing breeds would simultaneously eliminate this welfare problem and improve product quality.