Kay I answered you PM, but that photo on here is fine, so disregard my offer.
Is that growth hard at all? By the looks of it, it appears to be a supernumerary if that can exist in turkeys (Normally reference to teeth

) It appears to be a part of a spare leg, at least like the scales on a leg and may have been a defect right from the start? How long has it taken to grow that long, is it still growing, and at what speed at present?
I see he is 12 years old. When did it first appear?
Can you catch him and examine it really closely to see if it is like fingernail that can be clipped, or does it have a blood supply?