This problem is caused by Cnemidocoptes pilae, the scaly face (or scaly leg) mite.Tx is ivermectin either topically or orally. WARN owner of two things: 1. Even after successfulTx, beak deformity may persist. 2. Immunocompetent birds generally not affected, so this one may be immunocompromised. In passerine birds (especially canary, European goldfinch), look more for crusts on legs and digits ("tassel foot"). Dermanyssus gallinae  (or the feather mite) rarely affects psittacines and would not result in these encrustations and deformity. Squamous cell carcinoma is more common around mucocutaneous junctions of the head, wings, and phalanges. Fibrosarcoma can be locally invasive and could distort the beak, but would not be present in multiple, distant locations. Xanthomas are typically yellow, fatty masses in a subcutaneous location. They can be found anywhere, but the distal wing, keel, and sternopubic area are more commonly affected. Ref: The Merck Veterinary Manual online. Image courtesy of Uwe Gille.