we've two silkie pullets (we hope they are pullets) about 2-3 months old. we just added three std pullets about 5-6 wks old (2 delaware and 1 brahma). the two delaware's ganged up on the silkies repeatedly but the brahma stayed out of it. one delaware, got a predator look in its eye and was the main aggressor. we separated it from the others and the "look" went away. we ended up selling the evil delaware and things have been calm for the 24 hrs since. but as chickens will be chickens, the pecking order decision process may set in again. we don't want any pecking or "jumping attacks." is it common that stds should be separated from silkies?