It isn’t very prominent in Pima county. The disease is caused by a protozoan that requires a worm host (such as a nematode, earthworm, or the cecal worms of other poultry) to live. Susceptibility depends on the poultry species. Turkeys are extremely susceptible to blackhead, but chickens are fairly resistant. Ducks and geese are almost completely unaffected. Something to consider is that if you have both turkeys AND chickens together, the chickens can harbor the disease in cecal worms and pass it to the turkeys (it is advised to never house or range turkeys in areas that previously housed chickens). However, our dry soils are unlikely to harbor earthworms or nematodes to infect the chickens in the first place.