I too have kept chickens and turkeys (and ducks and geese) together for years. Big coop for them all at night and free range during the day. I too live in an area (Washington State) where Blackhead is not considered prevalent. In fact most vets up here don't even really know what it is, granted we don't have an avian specific vet. I never had any problems until I decided to purchase a pair of chukars from a farmer breeding them in Ritzville, WA. These guys had there own coop when I brought them home as they are quite little birds but they loved to free range with everyone else during the day. About 4 weeks after I brought them home they both died suddenly about 3 days apart from each other. I have never lost a bird in over 4 years, not even to a coyote so I had them necropsied. Both came back as Blackhead. This now meant that all of my chickens were more than likely carriers now and my 3 turkeys were at risk. My vet told me there was pretty much nothing I could do but butcher them (which I do not raise any of my birds for meat and could not bring myself to do this). They said that it is only a matter of time and there is nothing that can be done to prevent or treat Blackhead. A year went by so I thought I was lucky, then 2 of my Royal Palms dropped dead within a few weeks of each other. Both were necropsied and both were again Blackhead. My lesson in all of this and I hope to all of you is Blackhead can be a very big "huh?!" in your area and it only takes one bird coming into your flock or one wild bird for that matter and you have a serious problem on your hands. The chukars I purchased were housed with at least a hundred other chickens, guineas, chukars, and pheasants. I would believe that every chicken there (or sold from there) is probably a carrier and many of those game birds are infected or dead by now. This was a clean farm too, it wasnt like it was disgusting living conditions or anything like that. My one turkey that is left is doing quite well on a strict cecal worming schedule (which I wish the vet would have told me to do a long time ago) and is medicated with acidified copper sulfate and Fish-Zole whenever her poop gets the slightest bit yellow (the first sign of blackhead). But with the mortality rate of this disease in turkeys I know it is probably only a matter of time before it takes her too. All in all, you may get lucky keeping chickens and turkeys together but again it only takes one bird to change all that. If you are going to have both, it is best to separate them as best you can.