Leg health problems are the most significant welfare issue in commercial broiler chickens, with rapid growth rates causing lameness that affects the majority of birds in many flocks.
Broiler leg health represents perhaps the most significant animal welfare problem by scale in the world - billions of chickens annually experiencing painful lameness as a consequence of selective breeding for extreme growth rates that their skeletal systems cannot support. Severely lame birds cannot compete for food and water, creating secondary welfare problems from inadequate nutrition. Pain in lame broilers is confirmed by studies showing they voluntarily consume pain-reducing carprofen when given the choice. The welfare solution - slower-growing breeds - is achievable but requires industry and consumer commitment to higher welfare standards. The welfare cost of current production systems is borne entirely by the birds while economic benefits accrue to producers and consumers.