I have 3 girls that are 7 weeks and pretty much feathered out, and 6 girls that are only 4.5 weeks. We bought them all at the same time and they've been in the brooder together. We'd like to move the three older girls out to the coop next week, but we're worried that if we separate them, they will pick on the six others when they make the move to the coop in a month. Has anyone had experience with multiple ages in a brooder? Thanks!