I actually never combine mice from different colonies, so if you remove a female it's best to keep her alone with her babies for the rest of her life. I usually raise up one of her male offspring to mate back to her. If you keep the male in with the females they will have babies before the other ones are weaned, it actually works best to keep them in colonies so they can group nurse Otherwise you'll have one female and one male with old and young babies, just too much for one mom. Just keep one male to multiple females. Cannibalism is usually from young mice, they will get over it. If I were to throw all my tubs of mice into one big tub they would tear each other up until it was one big bloody mess. I've seen it at pet stores, it's not pretty.