Commercial turkeys have been selectively bred for such extreme breast muscle development that they cannot mate naturally and face significant welfare problems from their own body conformation.
Farmed turkeys represent one of the clearest examples of genetic selection creating welfare problems intrinsic to the animal. The degree of breast muscle development in commercial varieties is so extreme that the birds cannot engage in natural mating behavior, frequently have difficulty walking, and are susceptible to cardiac and metabolic problems arising from the metabolic demands of their extreme growth. Like broiler chickens, the welfare solution requires genetic reform — selecting for functional, healthy conformation rather than maximizing a single production trait. Heritage breeds that can mate naturally and grow more slowly demonstrate that turkey production is compatible with dramatically better welfare outcomes.