This behavior often prevents normal feather growth and emergence. Molting is the normal physiologic process by which old, worn feathers are lost and subsequently replaced by new ones. The frequency of this event varies with the species and the individual, as well as with climatic and geographic factors. The process of molting must be distinguished from feather picking. Feather picking is not difficult to diagnose.
Affected birds look very much the same.
This is, of course, because the bird cannot reach its head feathers. The one notable exception to this is the bird whose feathers are picked by a cage mate. As mentioned, birds caged together often engage in mutual preening. This behavior can become obsessive and destructive, resulting in feather picking. Causes of Feather Picking There are both medical and non-medical causes for feather picking.