HI, I have eight finches, 4 female and 4 male. They have a large cage but they are Very messy and I want to rehome 4. Can they be split up ? I don't know how we would be able to pick out "pairs" to rehome. I am open to having just boys or girls. I just don't want to so many and don't want to do anything that hurts them. Any suggestions? thanks!