As I have said before, I use a prong collar for Wolfie, just in case he decides to chase something. He's a good walker and doesn't pull, heels very well, but I am realistic enough to know that he can pull me anywhere he wants if he got it in his head to do so. Wolfie has a very strong prey drive. Just a few minutes ago, I took Wolfie out the cellar door to go do his business. As soon as I opened the door, he went crazy! There were 3 deer in my yard, and Wolfie wanted to chase them badly. He actually tried to pull me and got pinched for his efforts. So he barked, hackles raised, teeth bared, and standing up on his hind paws until they ran away. Thank goodness he was on the prong collar.