1. This may be due to fungal infection or bacterial infection. In this case, you should take the parrot to the vet as soon as possible for diagnosis and proper treatment.
It may be caused by insufficient nutrition or improper diet. For example, this may happen if parrots don't get enough vitamins and minerals.
It may be caused by parasites or skin diseases.
4. It may be because the parrot feels extremely nervous or anxious, which may be caused by environmental change, noise or other factors.
Whatever the reason, it is strongly recommended to take the parrot to the vet as soon as possible to ensure that it is correctly diagnosed and treated.