We have a mixed breed of seven different hens and up until last week, they all seemed to get along quite well. However, lately one of our lacey wyandottes seems to be having a tough time. The other chickens, particularly our one other wyandotte, have begun picking on her, pecking her so much that she's beginning to lose a significant amount of feathers from her neck (see the back of her neck in the photos below). Her comb has also taken on a slightly whitish/pink hue, rather than the typical deep red color she usually sports. Her diet has consisted of lots of laying feed plus some cracked corn, due to the low temperatures lately. She hasn't been eating very much, but I've isolated her for now with her own food and water - in addition to a heat lamp. Here are some pictures...any suggestions as to what else I should do?