yeah, it sounds like Jasper is resource guarding. That can be a sign of dominance, some obedience classes would probably help it a lot. Even if you guys have been thru obedience, good refresher classes are really helpful!! You should also start him on *strict* NILIF to end this, and try to get your whole family involved. I know you tried that with Piddles already, and it helped right? Jasper needs to know that everything he gets comes from YOU, and you can take it away whenever you want.

sorry Robyn, this stuff sucks, but Jasper is a good boy and a little bit of training and what you've been doing now will help him.