I have 7 Great danes living in my home. Some are mine and some are rescue dogs. I have dog fights occasionally. Any thoughts or suggestions?

Hi. I have 7 Great Danes living in my home. I did rescue for a while and have in the last year quit as it is to hard emotionally and financially on me and my dogs and family. Anyhow, I do have dog fights occasionally and I know that is probably normal since I have so many dogs. All my dogs are altered. I have two females that are both deaf. One of them is mine and the other is a rescue that will be adopted when the time comes. I have to be on watch at all times with all of them as in a moments time I can have a fight on my hands.
I am only about 118 pounds....5'2" tall and most of the time I am alone...so I have to break up the fights alone. Any good suggestions on separating them when I am alone? I have started to do the grabbing both legs of one dog and pulling them off but honestly sometime I am not strong enough physically. One time I had two males start to fight and I broke them
up....then as soon as they were broke up two of my other males started. That was horrible. I was screaming...but will stop doing so if it does not work. It did not work either...ha ha. Just upset me more. My biggest Question on Dog Fights or concern is this. My 2 yr. old Great Dane, Odin, went to my boyfriends house and stayed about 6 weeks with him because he had a fractured tibial crest and he was not healing here with all my dogs. Things went fine until just last week. Kevin, my boyfriend, has three females. A Great Dane, a Dobie, and a Boxer. All but the Dobie are spayed. Odin and his Great Dane got into a fight one early morning with the Dobie....Kevin says it was pretty bad but stopped as soon as he yelled at them...then Odin and the other Dane got off the Dobie. Three days later Kevin's X was over and let all three out together. They were out only for a matter of 3 minutes. He went to check on them and Odin and the other dane again were on the dobie..had her on her back. Kevin said he yelled at them....and Odie picked the dobie up under her front leg (armpit?) totally OFF the ground and shook her. He dropped her when he saw Kevin coming. The dobie was hurt pretty bad and had to be stitched up in several places. I think he would have killed her....if someone would not have stopped it. I am so upset....Odin has been in fights...but normally the other dog starts it. He is usually on the losing end....but never has he done anything like this. He is the dog I would have trusted the most....he is sweet natured and patient....Any thoughts? Of course now Kevin does not want Odin anywhere near his dobie...and I am not sure I trust him. I am wondering too if I should have him crated during the day or in a room by himself as I normally leave him out with a female dog that he gets along with. Any thoughts or suggestions?

I know I need to find homes for some of them but it is not easy. 5 dogs are mine.....the rest are up for adoption but I am picky when it comes to homes.

Thanks,
Steph (Kentucky Great Dane Rescue)