Psittacine Beak and Feather Disease

Psittacine Beak and Feather Disease (PBFD) is a devastating viral disease that, has been diagnosed in many species of birds, including African Grey parrots. PBFD was first noted in Cockatoos.
Young greys are most susceptible and suffer a more acute form of PBFD. This occurs as a baby during the first feather formation and after replacement of down feathers.
Older birds develop a chronic form where the feathers stop growing shortly after emerging from the skin. The feather structure becomes worse with each molt. They become curled, deformed, short and clubbed. Eventually, most feathers will be lost and the Beak may become affected.
Death is usually secondary to the disease since PBFD patients are immune compromised. There is no cure. It is spread through inhalation , ingestion, and also through the dust of an infected bird.

PBFD by Margaret A. Wissman, D.V.M., D.A.B.V.P.

Wikipedia

PBFD by Holly Nash, DMV,MS

PBFD at Avianweb

Bird Mart dangers at Avianweb