Fast-growing broiler breeds develop respiratory problems and cardiovascular disease due to extreme growth rate selection. Adopting slower-growing breeds significantly improves bird welfare.
The welfare cost of extreme growth selection in broiler chickens is now well documented. Birds selected primarily for rapid breast muscle growth have skeletal, cardiovascular, and respiratory systems that cannot keep pace with their body size. The result is widespread suffering: lameness from leg joints unable to support disproportionate body weight, respiratory distress from hearts and lungs overwhelmed by growth demands, and contact dermatitis from birds that spend excessive time lying due to their inability to move. Ascites — fluid accumulation in body cavities from cardiovascular-respiratory failure — causes slow death through suffocation. The solution is straightforward: adopting slower-growing breeds that have had less extreme selection restores more normal physiological function. The Better Chicken Commitment — adopted by hundreds of food companies globally — requires switching to slower-growing breeds by agreed timelines.