It is normal for a female budgie to have a very crusty brown cere when in breeding condition. However, if this is not the case, you may have a budgie with scaley face mites.
Symptoms: Beak deformity, encrustation of the cere, nasal obstruction, lameness of affected legs and feet
Description: Scaly face/scaly leg disease starts from the beak and spreads to other areas of the head and body.
Treatment: Ivermectin is the most common treatment for scaley face mites and can be obtained at your avian vet's office. It is always a good idea to have this condition seen by the avian vet so that it can be officially diagnosed and so that you can be instructed on the proper course of treatment. Scaley face is fairly common and normally takes only a couple of weeks to disappear after beginning proper treatment. Because it is contagious to other birds, it is wise to keep the affected bird away from all others and it may be necessary to treat your entire flock. Finding an Avian Vet
Budgie affected by scaley face mites.
This is the same budgie about
one month after treatment.