I have 2 male boxers, 1 is about 4 years old and neutered, the other is 1 and a half and not neuterd. The 1st one is the dominate male. Recently we got a female boxer puppy. The younger male is showing ownership of the puppy and will not let the elder male next to her. They had a serious fight for the first time ever last night about it. What can i do to prevent such a thing from happening again? I have to keep them seperated cause all they do is Growl at each other. Please help