I was going to suggest smaller prey, but you said that didnt work. At this point, I agree that a vet visit is in order. As for the whole feeding in the enclosure thing, I feed my bp and my Colombian boa in their enclosures. I have never noticed any changes in aggression. They are both totally fine when I reach into their tubs, and have never struck at me. It's up to the individual owner in the end, but even my previous boa (8+ feet) was never more aggressive than normal when I fed him in his enclosure and he could be pretty intimidating.