Little Mean Bastard Dogs

So I had to dog sit my uncle’s 3 dogs one weekend and I came across an interesting thing that one of the dogs would do. This dog is kind of a runt. He’s half the size of the other 2 dogs so he gets picked on a lot. And the only way he fights back it seems, is that once you give all 3 dogs a treat, the 2 bigger dogs will eat their treat while the little guy won’t. Then he’ll put the treat out in front of him and entice the other dogs to get it, but as soon as they get close, he puts it back in his mouth just to tease them and repeats the process as soon as the dog walks away.