I have 5 chickens, an Orpington, 2 Americaunas, a Silkie, and a Black sex link. Black sex link has been staying in her nesting box, when she does venture out her hackles are up, very nervous, scattered and agitated. She did have poop stuck to her backside which I took care of. She did lay an egg yesterday so that took away the bound egg theory. We did have a Silkie rooster which we culled. We hated to do it but he was MEAN. The Sex Links changed after he had his way with her. Rooster has been gone for about a week. Sex Link is still acting strange. Noticed today, one of Ameracaunas kept chasing the Sex Link and pecking her. I do have some antibiotics should I begin giving her some. I know chickens will try to go after sick chickens which is what seems to be happening now. Should we separate her from the flock and from camping out in her nesting box.