Well i can't say anything without actually seeing that. Maybe they are just playing or something?
Animal "play" can look pretty brutal.
Of course if they draw blood it's not play ;p
Given that there's blood all over the floor of my kitchen, and I still have the scar from where they bit me from the last time I had to deal with this crap, I can say that it's not playing.
They are probably fighting for dominance then. Pretty much literally over human affection i guess.
https://petdoctormom.wordpress.com/2011/12/04/why-are-my-two-dogs-fighting/
Might help might not.
That was fairly interesting. It probably is a dominance thing. It's strange, or probably not strange, one of the fighting pairs are the two that tend to claim most of the food(stepdad just dumps it into several bowls without any set "ownership" to any of them). Of these, one of them, a male-neutered and entered the family later than the rest because we originally gave him up for adoption but took him back when we found out he was being abused, has a tendency to growl at the other dogs when claiming his food, but does not resist if they eat anyway and will growl even if the other dogs are not nearby. The other, the only female(spayed), will sometimes growl, but mostly she just pulls the bowl towards her and often actively shares with the other two.
The other pair, one who was born sterile, will growl like the other one, but
never when the other growler is around(he gives up his food then), while the other male(not neutered or sterile) tends to just eat.
I'm a little worried about that suggestion to just leave the room. While last night they sorta calmed down a bit after I went into my room to escape the extinguisher chemicals I sprayed on them, and started back up when I came out to check on them, it also seemed a bit wrong to leave them to kill each other. On the other hand, we have never seen a case where they fought when nobody was home.