The density at which broiler chickens are housed is one of the most significant drivers of welfare outcomes. Higher density means more competition, more disease, worse air quality, and worse welfare.
At commercial maximum density, broilers in their last two weeks are so crowded that movement is severely restricted. The inability to move freely causes leg problems, prevents normal social behaviour, and forces birds to live in their own excreta. Ammonia from wet litter at high densities causes painful chemical burns on breast and hock skin. Respiratory stress from poor air quality impairs welfare and health. Research consistently shows that reducing stocking density improves welfare indicators including activity levels, gait scores, and leg health.