The genetic selection of broiler chickens for rapid growth has created breeds that suffer from skeletal, cardiac, and respiratory problems, making breed reform central to welfare improvement.
The genetic engineering of chickens for maximum growth rate has created birds whose bodies cannot sustain their own weight. Leg disorders, heart failure, and ascites cause chronic suffering in a significant proportion of the global broiler flock. The fundamental welfare problem is not a management issue but a genetic one - birds are selected for traits incompatible with their own wellbeing. Breed reform is the most impactful single intervention available.