I raised 5 turkeys, 5 guineas and 10 chickens together last year with no problems. Got them all at the same time as day old chicks and they grew up together. Had 8 hens winter over and this year added 19 turkeys, 2 geese and 45 chickens to the 8 chickens I had. Raised them in the house, them put them in the coop which was divided by wire so they could see each other and interact socially, but not physically. After a week or so, I let them all mix together. Never had any problems, but they do create their own pecking order. The geese were always biggest, but never really pushed their weight around. The old hens pick on the smaller chickens, even still. Mostly pushing them off the top roosts and making them eat last. The turkeys are now the biggest and they push the chickens away from the food until after they eat. But I have never had one kill another, or injure each other. Maybe Im lucky, who knows. My turkeys have always roosted in the coop, but my experience is they prefer the shelf to a bar roost. Never did figure that one out. And I have never had a problem with diseases, either.