We have ten two month old chicks, including two Silkies. They are in a small coop inside a large run and we have slowly been introducing them to our flock of older hens (we'll do this for two more months... they can get to know each other, but are separated except for a few minutes each day). Our Red Sex Link, Welsummer and Wyandotte are fine with the chicks, but the Australorp is really aggressive and predatory (she is the lowest in the adult bird pecking order, go figure). We used to have an Old English game hen bantam with a flock of standard sized hens and she was fine and never got picked on. I think you can have a flock of mixed bantam/speciality/standard birds as long as you have plenty of space and no aggressive personalities. I like the advice in the article Michael OShay posted about putting food treats or CDs in different parts of the coop when you're introducing new birds. I'm going to try this as we slowly integrate the two bird populations.