I raised two tom turkeys with my RIR hens. The only problem was that the toms tried to mate with my much smaller hens. I sold my hens do to health problems and then 1 month before Thanksgiving my wife and kids tell me they can't eat the turkeys. I got rid of the Turkeys because of health reasons and bought a fresh dressed tom turkey.
They had no health issues that I ever saw and I had them checked before I sold them. I know several other people that have small flocks and they have had no problems either. They do say that turkeys can get blackhead from chickens. I guess you might take a chance if you did it. Other people in Eastern NC do it all the time. Like I say these are very small flocks. Most of these flocks are under 25 or 30 birds. I know one old timer that has most everything such as Turkeys, chickens, ducks and geese. He even has a couple of small goats in the fenced in area. It looks like a petting zoo there.
I hope this helps. By the way. I am doing better and plan on more chickens and Turkeys but, my kids fixed up a place for our PET Turkeys. It is on the other side of the 3 acre plot we have. I am trying to raise some Black Copper Marans and do not want totake any chance with that type of poultry. Good Luck, Dave in NC