The Broad Breasted White dominates commercial production. Decades of selection for pectoral yield have shifted the bird's centre of mass forward and enlarged the breast to the point where the cloacal contact required for mating cannot be achieved. Adult males of these lines can reach twenty kilograms or more, well beyond anything a wild turkey attains.
The industry response, adopted from the mid-twentieth century, is manual semen collection and insemination of hens on a regular cycle. Without it the commercial lines would not reproduce. This makes the world's dominant turkey genotype wholly dependent on human intervention for its continued existence, an unusually stark case of a domesticated form that cannot complete its own life cycle.
Heritage breeds such as the Bourbon Red, Narragansett and Standard Bronze retain natural mating ability and the capacity for limited flight. They grow more slowly and yield less breast meat, which is precisely why they were displaced. The wild ancestor remains abundant across much of North America following successful twentieth-century restoration.