I have 7 chickens who have been living together since chicks and are now 2 years old (no roo). Everything was fine until a couple of days ago when they started to pick on one of my buffs. She never tries to fight with anyone and just runs aways. All the chickens, even my smaller girl who is very sweet has snapped at her. I have no idea why they are doing this. She even dreads going into the coop now. There has been no blood and it is NOT constant, but they do watch her and I can see she avoids them. I can't find one thing wrong with her. Could she be sick and I don't know it? Could the other chickens sense it and that is why they have suddenly turned on her? What reasons do chickens who have lived happily together suddenly start to single one out who has done nothing wrong?