Given that Clio has wanted to be the dominant rat pretty much since she was born, I was not expecting this to be a complicated decision. The little guys are active, sure, and have been spending quite a lot of time practicing wrestling each other, but they're less than half Clio's size. However, Clio is in heat just now, so she seems only too happy to, er, be on the receiving end of certain dominance-related behaviors. Frankly she looks more surprised than anything.
Perhaps she will get around to squishing the little rats into their appropriate hierarchical rank in a day or two.