thats good that he has found a game that he enjoys (be it not the best type of game) one that encourages growling and biting, but it is a game maybe you could work on other games. if you check out the thread how to teach fetch you may get a few tips.

but a couple of comments/questions (just what i think) if you knew henry was a abused dog why did you hit him when he went after the cat the poor dog had obviously been through hell and then he goes to your home where he is meant to be safe and cops more abuse ~shakes muuh head~i just dont understand.