I cannot answer that question...and doubt many bird owners can since there could be genetic or food related issues. . We've had our Umbrella cockatoo for over 35 years with no such problem. I would strongly suggest you contact an avian veterinarian or the avian specialist at a major zoo. We have used LaFeber's vitamins all his life. He will likely outlive us. BTW we also feed him fresh vegetables, beet stems, small pieces of corn on the cob, bok choy leaves, mango, the tender inner parts of celery. Seed alone is not sufficient for a healthy diet.

When I got my conure he was feather challenged, and still is—he is missing chest, back and under wing feathers. Finally discovered this is why he nips, screams, pulls feathers etc. when he’s itchy. Have been applying a Natrapet plumage and skin conditioner, but lately it’s getting tricky to apply, he needs it daily—quickly dab his skin with the liquid, really calms him down—proof the itching really aggravates him. Recently added red palm oil to his food, recommended by bird store. Also going to upgrade his vitamins to better quality since he’s a seed eater.