KYS is still correct about one thing. We who learned training in the movie business know that hunger is often the key to learning. If your dog doesn't respond to treats, he's not hungry enough. Now don't get me wrong -- I'm not talking about starving your dog, but they can go a lot longer between meals than humans can. Even for a well trained dog, we don't send them out to do a dog food commercial with less than 24 hours hunger. That's not much considering some working dogs are fed only every other day. I bet that sends shivers down a lot of your spines. The other thing to consider is your dog's breed. He's A LOT hotter than we are. Even in 70 degree temperature, he's very hot and his mass stores that heat. Your dog will perform his best when it's colder. Train early in the moring or in the evening or just wait since you're in Vermont if it's not already pretty cool in the daytime by now.