Modern broiler chickens have been bred to grow so fast they develop chronic health problems, with the vast majority of commercial chickens experiencing welfare compromises from their genetics alone.
The genetics of modern commercial broilers represent one of the largest single sources of farm animal suffering globally. Rapid growth rates have been selected without adequate regard for the skeletal, cardiovascular, and respiratory systems needed to sustain that growth. Leg weakness affects the majority of birds and causes chronic pain that reduces mobility and feeding. Breast blisters from prolonged lying in contaminated litter cause ulcers. Ascites (fluid in body cavity) from cardiovascular insufficiency causes suffocation. Sudden death syndrome affects a proportion of rapidly growing birds. Slower-growing breeds demonstrating 25-30% reduced growth rates show dramatically improved welfare outcomes with lower rates of leg weakness, cardiac problems, and behavior abnormalities. The Better Chicken Commitment campaign is driving retailer commitments to adopt slower-growing breeds.