Fast-growing broiler chickens develop painful leg disorders at alarming rates due to selective breeding for rapid muscle growth. This represents one of the most significant welfare problems in animal agriculture by scale.
Rapid growth in commercial broiler chickens creates skeletal and cardiovascular systems that cannot support the massive muscle mass. Leg disorders cause chronic pain throughout the final weeks of a birds life. Research using preference testing shows lame broilers choose analgesic-laced feed over normal feed, confirming they experience pain. The scale of this suffering is enormous given the 70 billion chickens slaughtered globally each year. Birds with compromised mobility cannot access food and water, leading to dehydration and starvation even in well-managed flocks. The fundamental welfare problem lies in the genetics of fast-growth breeds, which cannot be resolved without transitioning to slower-growing varieties.