We currently have 16 chickens- 11 Rhode Island Red hens, 1 Rhode Island Red rooster, and 4 Delaware hens. A dog had killed some chickens from our flock so we ordered some replacement chicks- 2 Delaware roo's and then 9 buff orphington hens. We also have 6 black sex link roosters that came with our new order "for comfort/warmth" that will probably go to the freezer soon. Anyway, the chicks are about 11 weeks old, and fully feathered out. We had been keeping them in a miniature coop in sight of the other chickens because it's inside the run, but when we tried to mix the flocks today the RIR hens attacked one of my Delaware roo's and he was scared to the point that he was playing dead. The RIR's also pulled some of his feathers out. I suppose we need to wait a little longer to introduce them to the flock, but it seems that the RIR's are the problem as far as being aggressive towards the newbies. The Delawares don't bother them- but they are the bottom of the pecking order anyway. The only problem is that the chicks are outgrowing their new coop, and with them being almost 3 months old, we thought that would be a good time to introduce them to the rest of the flock. Any suggestions on mixing our flock? I'm about fed up with the RIR's...the rooster included- and if the hens weren't laying so well they'd all be going to the freezer.