I'm really concerned about what's happening in my usually peaceful coop. Suddenly after living together peacefully for a year several hens have singled out one hen and started jumping on, chasing, chasing away from food and water, corner her and even block her from going inside the coop at night. They actually sit directly in front of the entrance and won't allow her to enter. I'm worried and dumbfounded by this. They have ALWAYS got along find, no conflicts, just very pleasant. A little about the chickens, housing and so on.... If that has anything to do with this. The coop interior is about 10x12, one wall is mostly nest boxes (16) with a perch at each level, 2 big perches floor to ceiling 32" wide x 8' tall, kind of like a wide ladder and one has a nest box on top of it for a little game hen who likes to be as high up as she can get. 11 hens, 2 prod red, 2 wyandott, 1 ameracauna, 1 Cochin frizzle bantam, 1 mixed bantam, 1 polish frizzle bantam, 1 tiny old English game hen, 2 silkies and 1 silkie roo. The outside coop run is 20x20 with lots of perches, a few nooks and cubbies, food and water area. Fresh layer feed, fruit, vegetables, water every morning. Usually treats in the afternoon. The one that's been singled out is a silkie, her sister silkie, Lucy the game hen and the roo are the only ones not picking on her. I set up anotjer feed area so she can eat and Lucy will eat with her, the others will eventually run her off this food as well. I have to carry her into the coop at night. I don't get this at all. They've been raised together, never a problem until this last week. I don't see any injuries, infestation, she does seem depressed now. Does anyone know why something like this would happen, what I can do? Any advice, experience, insight I would greatly appreciate.