This is often a sign of illness, poor nutrition, or an imported bird to northern latitudes. Some birds have poor feather condition because they are unable to preen. This condition can be the result of a neck or back injury. Some hand raised babies may have never learned the finer details of preening and therefore, have an unkempt appearance. Feather cysts are ingrown feathers that can occur in cockatiels as well as other species.
Surgical removal is the only way to correct the problem.
Baldness is a genetic problem in lutino cockatiels and hormonal in canaries. Papovavirus has been implicated in delayed feather replacement after a birds first mold of wing and contour feathers. Feather picking is an obsessive, destructive behavior pattern during which all or part of feathers are pulled out, amputated or damaged. This must be distinguished from normal molting and preening behavior. The appearance of the feather picker is always the same.