this is the hardest question all terrier men have to ask themselves,what age? answer,dont know!! nobody really does,each dog is different,it is very hard to keep a young dog back if they are mad to go but we should. i have a few youngsters at the monant,one started like a steam train at 10 months,no regard for herself and no respect for her quarry,the other was the cautious type eager but not quite sure. the first one now is starting to show signs that she is not going to be the real deal and the second one is flying and is being dug to regular now at 21 months!! the first one,is out of a bitc