I have a 10 week old bull terrier cross staffy. He bites and most of the time when u say drop or no her will stop...However sometimes it seems to just make him worse and he bites down harder and runs at u to bite u and nothing I say or do seems to work. I put him in a time out in a separate room to try and calm him down and correct this behaviour. Sometimes that works and sometimes it doesn't but he often makes me bleed. We have an older pure staffy age 7 and she is very placid....she used to play with him but now my older dog doesn't want to have him anywhere near her and will tell him off....of course he doesn't listen. I am worried my new dog is showing aggresive behaviour but I don't know because we got my other dog at 8 months so I have never owned a puppy this young. Am I doing the right thing? Is this aggression? And will he grow out of it.