I'm not sure about puppy behavior, but my dog is a big breed dog, he's 10, and he'll go through spells of not eating alot. He quit eating when we had to bored him, and he stopped for a while when we brought the kittens home. Just keep trying different things and if he dosen't eat it, either take it away, or leave it out and see what he does. That's all I can think of.....hope it helps.