I recently got 30 new chicks - 4 of them are 7 weeks old, and the others range from 1-3 weeks old. Right now they are all staying together in an 8x8 outbuilding. I have the 7-weekers in a cage next to where the little ones hang out with the brooding lamp, as I didn't want to risk the older ones picking on the little ones. I was wondering how long should I give it before I mix them? Thanks in advance!