I have 1 Silkie hen that is losing feathers on her head only. She looks worse everyday. I treated for lice/mites twice recently with poultry powder but she is still losing feathers. I am not seeing anymore lice or mites. I have 4 chickens in all ( 2 golden comets and 1 silkie roo) and the other 3 are fine. She is not losing feathers anywhere else and is not being picked on. They were born in March so I don't think it is a molt. Can anyone help?