I have a big old Brahma hen. The person I got her from said she was an old hen when she got her. I'm not sure how old she is, but she's old! She stopped laying about a month ago. Two days ago I saw she has lost a lot of feathers around her vent. Then the next day she was missing feathers all the way around her neck, under her wings, her chest, her saddle area is totally bald. The feathers are falling out, they are not breaking off. There are patches of bare skin all over her. The feathers are all over the hen house and outside everywhere! Its getting cold outside and she'll be naked soon! What's going on?? Does she have a disease or is she just old and on her way out?