In no way am I trying to give advice, I've had turkeys less than 6 weeks. This was just my experience.
I bought a year old bourbon red gobbler and a couple young bronze poults at a sale 6 weeks ago. I let them roost in the barn, where one of the stauls is converted to a chicken coop where I have about 30 chickens. The turkeys roost in the rafters(old tobacco barn) and free range all day. I let the chickens out, first thing in the morning, they free range all day also. I didn't know about the dangers of keeping turkeys with chickens. After about 3-4 weeks, the tom and ond one of the poults became very sick. Sitting all puffed up, not eating or drinking. Just resting in the sun, acting depressed I couldn't get a vet to see them. One vet told me"most people just throw sick birds on the compost pile." I read everything I could online and in books and guessed it was a case of either blackhead or cocci. I read so many contradicting things and I didn't know what to do. I went to 3 local feed stores, nobody knew anything. I bought a livestock medicine called sulmet, for less than $15, figuring they are going to be dead soon, why not try something. The sulmet I bought is supposed to be placed in their drinking water. This wasn't an option, since they were not drinking to my knowledge. When they are drinking, they share a 50 gallon tub with llamas and there is a creek. I estimated how much they needed, (more of an uneducated frustrated guess) I shot 6 mls down the gullet of the older tom, and half that down the younger birds. I gave them the first dose around 5 pm, by morning they were acting almost normal. I dosed them again on day 2. On morning 3 I was awakened by the tom gobbling outside my window. I then cut the dose in half and treated them for 4 days. It's only been about 10 days but they seem happy and healthy.
Again, I don't know what I'm doing, but out of desperation, I took a shot in the dark, and it seems like I got lucky. I didn't have a proper diagnosis and I didn't follow the instructions with the medicine. I'm just saying, if your desperate and can't find any help. If it were me, I'd rather go out swinging