HI Brad, welcome the forum.
Regarding your bruisers, It's always hazardous to give advice without seeing the whole picture but it sounds to me just a battle to be the top dog. Equality doesn't exist in the dog world & being of the same sex, there's gotta be one more dominant than the other. Generally in this situation it is best to let them sort it out themselves, if you break up a fight each time one starts, you're preventing a hierachy from establishing which is necessary for them to live in harmony together & because of the frustration, each fight will become more violent as the position of each dog remains unclear.
Hierachical dog fights can be very alarming, but they are highly codified & serious injury is rare unless both dogs are dominant, but it may be too late now to allow them to establish a hierachy doggy style..Castration won't help in this situation as it's not hormonal.
You could ease the situation by giving the more dominant of the two (it should be obvious) priority over the other, such as feeding, putting on lead, greeting/stroking etc. first, .in this kind of scenario, it is common for owners to privilege the dog they've had the longest, since they feel they are letting it down otherwise but unless it is the more dominant, such behaviour will only worsen the situation. If the newcomer is the top dog, then giving him the privileges of his rang will considerably lessen the tension & if he growls at or tries to intimidate your older dog, let him, he is merely affirming his dominance.......don't let it break out into a fight though in your presence. Once the hierachy is clear & it may be that your older dog is the less dominant, he will be much happier.
Last edited by Blacktimberwolf; 18th-October-2016 at 04:54 PM.
Properly trained, a man can become a dog's best friend.