Most of the general comments lead to the conclusion that dogs are individuals, just like people, and they only respond to the training teaching they are given on top of, or in spite of their natural instincts. Although I guess it is a part of training, socialization is the key to level behavior in most dogs. That means you need to get them early, but controlled exposure to lots of "stuff", noises, smells, people, other animals (not just dogs) will do wonders for even a dog with strong instinctive behavior. No, I'm not a vet or any professional anything, just a dog lover. We have even had some older dogs who can be socialized in the right atmosphere and recover from some bad teaching. Give them a chance and firm boundries and they will grow up good citizens, usually. (Kinda sounds like rearing kids, doesn't it?) JMHO