Hello, @dalovesroosters!
I too have a turkey housed with my chickens. I originally did it in hopes it would provide environmental vaccination against Marek's, since strain that is used to vaccinate chickens is Turkey Marek's. I have no idea if it works or not but I have seen the added benefit from my turkey of having less attention from aerial predators.
To protect against blackhead (just in case), I give her a couple of capsules of cayenne pepper each month. She eats them like candy.
I have read cayenne kills blackhead nematodes so either we just don't have blackhead in the soil or it's doing it's job. 
I too have a turkey housed with my chickens. I originally did it in hopes it would provide environmental vaccination against Marek's, since strain that is used to vaccinate chickens is Turkey Marek's. I have no idea if it works or not but I have seen the added benefit from my turkey of having less attention from aerial predators.
To protect against blackhead (just in case), I give her a couple of capsules of cayenne pepper each month. She eats them like candy.

