Animal Welfare Professionals

I'm a volunteer at a cage free facility and we have a male cat who is really aggressive to mostly females in the room he is currently in. Our intake is primarily kittens who go to fosters from our local shelter then to our 4 room facility once they have been neutered and vaccinations. Donny was a loving kitten to all the other kittens in his room when he arrived. Being an orange tabby he was overlooked and has been with us almost a year now. When he outgrew the kitten room he was moved to the young adults. He immediately became very aggressive with all other cats even those he had previously been fine with. We put him in a large two story kennel thinking this would help him decompress. It worked for the cats he was used to. Unfortunately kitten season never ended and every time we put a new cat in his room he would go into attack mode. We then moved him to our largest room thinking this would give him space. Now he's turned into an all out thug. We have had to remove two cats from that room because they are loosing weight. He likes people and has two cats he actually loves on, both males. We just can't get anyone interested in him when they visit because he's constantly attacking other cats. Really need help. He's a sweet cat, who would make someone a great solo cat. But he now has a bad reputation. Any advice would be appreciated.