females tend to be more dominant, and can see a new chin in there space can cause them to think "intruder!" where as putting a femail into the pre existing male's cage, it is more likely seince they were there first, and she is the newcomer, she will be a lot less likely to outright reject them, and more likely to try to be friendly. males dont seem to have many problems sharing a cage with other males, but females seem to be more moody twards any new chin in there cage if they are used to having it all to themselves.
