At 15 it'll probably go green quite quickly. Apparently not an issue and we've eaten chickens with green tinted skin but not all that appealing. Agree with the fridge idea. The bird just need a bit of rest and 'controlled decay' before freezing / eating as it tenders the meat and adds flavour. But it needs to be cold as a fridge, certainly if you want to sell them / give them away. I keep looking for a cheap larder fridge to use so I can hang them but currently just put them in a plastic box and on the fridge shelf. Appreciate that might not be so easy with turkeys.