Modern broiler chickens have been selectively bred for extremely rapid growth, reaching slaughter weight in 35-42 days. This accelerated growth creates severe welfare problems including leg disorders, cardiovascular disease, and inability to support their own weight.
The welfare of fast-growing broiler breeds represents a systemic problem built into the genetics of the animals. Birds cannot walk normally, cannot support their weight comfortably, and suffer chronic pain from leg problems and pressure sores. Cardiac failure kills birds before slaughter. This suffering is not an accident or management failure - it is the result of deliberately selecting for growth rate without adequate welfare constraints. Switching to slower-growing breeds is the single most impactful technical change available to the broiler industry for welfare improvement.