Modern broiler chickens have been selectively bred for such rapid growth that many develop leg disorders that impair their ability to walk. Walking ability is one of the most important welfare indicators in poultry.
Lameness in broiler chickens is one of the most widespread welfare problems in modern animal agriculture, affecting hundreds of millions of birds annually. The inability to walk normally prevents chickens from accessing food and water, engaging in social behavior, and avoiding aggression. Lame birds experience chronic pain that is measurable through behavioral indicators including reduced movement, altered posture, and willingness to accept pain relief medication. The root cause — genetic selection for extreme growth rate — is modifiable. Slower-growing breeds produce birds with dramatically better welfare outcomes. Consumer and corporate demand for higher welfare chicken is the primary driver of breed changes in the industry.