Male to male aggression is typical in the Doberman breed. It is not recommended that multiple males be kept together. Actually, that is quite normal with some working breeds.
My friend had a male Rottie (altered), 3 years old. They decided to add a Bull Mastiff to their family. Everything was fine while the Bully boy was a puppy, things started to get ugly when the Bully hit adolescence. The Mastiff was trying to take over the alpha position, while the laid back Rott wouldn’t start the fights, he would finish them. They had the Mastiff neutered, but even that didn’t solve their problem. The situation wasn’t ideal for either dog, the Rottie was always having to defend himself and stay on alert and the Mastiff was not content to be second in command; it was a very stressful situation for everyone involved.
I have seen many experiences of male aggression when the males live together. Dogs don’t have equal rights; they have ranking system of alpha (the top dog) and those under alpha. Sometimes people get lucky and one submissive male might accept the lower position (not typical of Dobe males) but the stories of male aggression is common in Dobermans and sometimes they have very sad endings with one dog getting hurt very badly. Stories of puppies getting along are fine and somewhat expected; it is when the dogs reach adolescence that the problems arise. Here is a link for a similar situation:
http://www.kinetic-unity.com/males.html.
Some people might say, my male dog plays great with other male dogs; he doesn’t mind them at all. That is what happened in the above situation too, the Mastiff would play wonderfully with visiting males or other male dogs in other places.
There is a HUGE difference in playing with other dogs verses living with them and having to share resources on a daily basis.
Resources are anything the dog likes, toys, food, a sleeping spot on the couch or bed, attention from a person, bones, etc. A lower dog wanting to take over the alpha position will try to challenge people or dogs for these items creating much conflict. Don’t think that just because your male gets along with other males that he will tolerate another male living with him on a daily basis. Pack dynamics are different with every dog and vary with each situation.
Doberman rescues usually don’t allow multiple male dogs to live together...too much of a risk in most cases.
I know several Doberman breeders keep their male Dobermans separated after they reach about 6-12 months of age because the possibility they might get into fights is high, this is also illustrated in the link given above. I strongly suggest if you want to add another dog stick with a bitch. Why risk the chance of two males not getting along, when the possibility is high that they will not.
