I think it is easy to give advice over the internet, but without seeing this dog in action, it is almost impossible to gauge the extent of the puppy's behavior. And while most of the advice in this thread is great for the norm, sometimes there are real abnormalities in behavior, beyond the typical puppy stuff. Is this where this Thylacine's puppy falls? I don't think anyone reading this thread can make that assessment. I'm also not convinced that anyone short of a certified behaviorist (not trainer, not typical DVM) can or should. Personally, if I were in this position, I'd get Brenda Aloff's books and follow her advice. I'd probably contact her and ask for recommendations on a behaviorist near me. I've been very impressed with her Aggression in Dogs dvd that I managed to get second hand. I have not made her aggression book a priority since I do not have this sort of problem with my current dogs, but it is on my wish list. But if I had this sort of problem with my dog, I'd have ordered it yesterday.
I posted this for anyone reading this forum who might be going through similiar problems since Thylacine seems to have dropped this forum. I have not ever used a shock collar, so I won't make suggestions as to which one is best. Personally, I'm pretty happy with the level of training I've achieved without a shock collar. <shrug>But I will say, that as the human in your relationship with your dog, YOU get to decide what belongs in that relationship and what doesn't.</shrug>