This can be a common problem in cockatiels. The replacement of a white feather by a golden yellow one may indicate a problem. A low grade psittacosis infection can be one of the causes of this condition. Abnormal molts can be expressed by dark areas or fringes of feathers that appear bronzed and frayed. 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.