+1 on what Gemmy said about crate training, and it does bite that it didn't work out....
The other problem could be two dogs of the same sex. Get one fixed so you won't have to worry about puppies, but the opposite sex usually won't fight for the alpha position. I had that problem when we had two males, Atticus nearly ripped the ear off of the Golden retriever my mother brought into the home...he was the sweetest dog, but he and Atticus were forever jealous of each other (I couldn't even pet one without the other horning in to push the other away) and they fought over chew bones and food besides. females are usually not as bad as males for fighting, but it is what it is.