We have a Seven year old Kakariki who has lost all his body plumage and only has grey down covering him. His head and neck and tail are unaffected. We have treated him and his cage for parasites with no change. We have not seen him over preening or displaying any behaviour to make us consider boredom. He has fresh water for bathing twice a week and is fed a varied diet of seed and fresh fruit and veg. We have no more ideas to try and hope that you can give us some answers.