I have 15 hens (of which 5 are EEs and 4 RIR) Just recently I've noticed one of my RIR basically stalking and attack in one of the EES. Neither of them Have been broody or sick or anything. Up till now (I've had them all together since last summer. My first batch is almost all a year old and the other group only a month younger) they have all gotten along amazingly well. They seem fine in the coop and run, but as soon as they free range the RIR will stalk and attack the EE. The feathers on my poor EE are looking quite pitiful, other then that she doesn't seem Injured or anything and they both get along with everyone else. What could possibly be going on and what should I do yo stop this.