Okay here's the situation, Dogs hide pain. They will act as if nothing is wrong. put the dog in a room with a window and go outside and look in without being seen and you'll have the real picture. If his hip is broken, I am sorry but there are only two choices: 1: have the dog tended by a...
A you might not be strict enough. Try to remember dogs play using their teeth, it's all they know and he may be trying to tell you what he doesn't like or he may be overexcited. This biting will get worse if allowed to continue. I suggest you firmly grab his muzzle look him dead in the eye...