This is what dogs do. It's called an "Opportunistic Feeder". Bud has been worked with from a pup about not being food aggressive. I worked with Jetta and Bud together. They let me move and take their food bowl from them and as a result they both grew up without aggression surrounding food guarding.
If you have a dog who is food aggressive, you need to keep children and other dogs away when feeding time comes. The dog should be moved to a different room. Bud could kill his little thief friend with one bite. Bud is such a good dog- he even shares his toys!