ooo I currently have a total of 14 cats. Not all are in the house obviously. There are three who have a cat door and come in and out. There are 9 who hang out at the barn (but have an enclosure they are put into at night due to the number of coyotes who roam the lower property) and there is one that is not ours, but comes to the back deck for food every night. The three who come into the house ignore each other for the most part. They all sleep in different rooms. The only time they "work" together is when they gang up on the dog. The barn cats who all get locked into the enclosure at night (it's actually half the barn including two stories and a totally wire meshed and roofed area of about the same size as the barn...some of those cats sleep in a big pile so you can't where one ends and one begins if it's a few of the black ones piled up together. They all get along.