Scientific evidence for welfare harms in fast-growing broiler breeds is driving industry reform toward slower-growing alternatives, with major food companies leading the transition.
The welfare case against fast-growing broiler breeds is now scientifically robust. Rapid muscle growth outpaces skeletal and cardiovascular development, resulting in birds that cannot walk normally, have hearts and lungs too small for their bodies, and experience chronic leg pain that limits their ability to access food and water. Slower-growing breeds that reach slaughter weight in 56+ days show dramatically better mobility, lower mortality rates, and improved cardiovascular health. The welfare improvement comes with real cost increases that require consumer and corporate willingness to pay more for chicken.