How long should I run my 18 month old boxer on a treadmill
Yes. If you make it too unpleasant for the dog, you will have a hard time getting him on it in the future. Walking is better if you have the time, because that interests the dog.
4 hours most likely
Not at once!! Check out Cesar Millar (dog whisperer) re how much you should exercise your dog to ensure they dont get frustrated from being cooped up & unable to run.
start at little amounts and work your way up and dont run it at first walk it then increase to a slow run