Hello. I’m new here and a little late to this thread.
A few thoughts: First, butchering an animal should have a certain amount of mental weight to it. That’s what separates us from the weasels

. But it doesn’t sound like you are jammed up on the intellectual side, but more a gut level response. It’s a heavy thing, but we have to figure out how to carry that weight until we get used to it. That leads to number 2. Desensitize! If you have neighbors ir friends who home butcher, volunteer to help them. Seriously, let the whole process become praticed and mechanical while working on birds you aren’t close to. 3. And finally, trade a couple birds with neighbors or whomever and let someone else choose the bird for supper. You won’t really know of you’re eating one of yours or a stranger bird.
I hope any of this helps.