My son has two boxer dogs - one a female aged around 8, the other cross boxer - male - aged around 2. Most of the time they get along really well however at least once daily they have a full on fight nearly killing each other - this lasts about a minute or so, then they are friends. Is there I can do to stop this fighting? The younger boxer gets the shakes just prior to a fight and I am worried they may kill each other eventually.