I have a 1.5 year old Mottled Java that has lost most of the feathers on her head and throat (see picture). She is not the bottom of the pecking order, I would say she is ranked 2nd out of the 9 hens I have. I don't have any roosters either. What would cause her to lose the feathers on her head? I have had her for about a year, she hasn't had any health issues and I have not found lice or mites on her. She does have some odd behaviors, she will sit by herself in the mornings or stand with her body all compacted and feathers fluffed as if it was cold. As far as I know she is laying. Good appetite and she is feisty towards the other hens. She used to be one of my meanest hens but has thankfully matured out of that but the other hens still respect her. Any ideas?