Hazel - the pheasant is an excellent meat for cats - lucky you, you have some. Our neighbour doesn't throw goodies over our fence for the cats.
I'd be starting to try to get a neck or 2 to test him on before thawing the whole bird out - to see if he'll eat it. Cats really are not fussy or don't like a change in food normally. Switching from commercial to anything raw could be quite a chore. But then, he might just like it and figure - Wow, this is something I could get used to.
If you are going to get into raw, suggestion that you use a really good recipe.
The problem you have is with JD being so small, you're only looking at about 50 to 60 gm for a full meal. So the pheasant would be pretty much a really really good supply of meat. Unless you can cut it up frozen and use it over a period of time for treats as well as the odd main meal. Thawing the whole carcass out at once, you'd be wasting a lot of good meat.
Due to the fact that at the present time he is having mouth issues, I'd be just using it as a treat or just sticking to the chicken necks, until the situation improves.
