Oh Milton...
It sounds like, since you did a thorough vet exam, that the issue is not a medical one.
I almost wonder if he is plucking out of habit now... Maybe he started plucking because he was stressed about you getting a new bird or because of the fireworks or whatever, and even though he may have gotten over that initial reason to pluck, he does it now out of habit...
I don't know... I think we, as humans, try very hard to rationalize everything. We look for reasons for just about everything. So when a bird plucks, we often beat ourselves up about it and think that, oh gosh, we've done something
wrong. But really, it is nothing that we did on an individual level. Sometimes the only reason a bird needs to pluck is to be a bird living in captivity... Which, of course, doesn't help us in our attempts to try and relieve the problem.
I'm sort of rambling here... I guess I just want you to know that you
are taking all the right steps. You're doing everything right, and you know Milton better than any of us, and although we can give you all sorts of advice, you'll ultimately know what's best for Milton.
That being said, I personally would worry about the ski mask sock buddy stressing Milton out even more, but I can see how it would make sense as a short term solution until the feathers grow back so that he doesn't pluck the itchy pin feathers. It might be worth it, though, to try the Avicalm or chamomile tea first and see if that helps settle him down. Hopefully the mask won't be necessary.
Hang in there. You're doing great.
