I have eight barred rock females that are already in the coop. They are 7 weeks old. I had wanted 2 to 4 more but didn't have room in the brooder at the time. I just bought 3 Rhode Island Reds and 3 Spotted Sussex, they are 3 weeks old. They are in the brooder. I'm concerned because by Barred Rocks seem a little aggressive to me. They are quite feisty and the Sussex are bigger that the RIRs right now. These new ones have totally different personalities. I'm concerned that even I do all the suggested things to integrate them, they will still bully them or kill them. I plan on letting them get bigger of course. Has anyone mixed these breeds with this slight age difference and when do you do it?