Modern fast-growing broiler breeds reach slaughter weight in 5-6 weeks but experience severe leg disorders, cardiovascular problems, and chronic pain as a consequence of extreme growth rate selection.
The extreme growth rates of modern broiler breeds represent one of the clearest cases of genetic selection creating intrinsic welfare problems. Birds bred to grow so fast that their cardiovascular and skeletal systems cannot keep pace are not exceptional cases but predictable outcomes of selection priorities that maximized growth rate over health. A significant proportion of commercial broilers experience chronic pain from leg disorders throughout their lives. Transitioning to slower-growing breeds that reach slaughter weight over 9-12 weeks dramatically reduces these problems while producing birds with improved welfare throughout their lives. The welfare trade-off for greater production efficiency is one that consumers and retailers have the power to change.