Feathers

written for NCS Magazine - 1988
By Dr. Jerry LaBonde, MS, DVM
Denver, CO

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Feathers are what separate the birds from the beasts. Their structure is more similar to reptilian scales than mammalian hair. Feathers have a variety of functions such as flight, temperature regulation, protections against environmental and climatic extremes, and courtship display. In the wild, birds with poor feathering condition do not survive, therefore careful attention to the feathers and their condition is vital. Birds will use their beak and feet to condition and waterproof their feathers and to meticulously remove sheaths through which all new contour and flight feathers emerge. This process is called "preening" and at times is common between cage mates.

Because birds hide their disease symptoms so well, poor feather condition may be the first sign of an ill bird. The feather condition reflects the physiologic and psychological health of the bird. Many feather diseases have an underlying diet or internal disease problem as well as a psychological disorder. Missing or unhealthy feathers can indicate and ill bird or obsessive preening such as feather picking. A continuum developed by Rosskopf and Woepel is helpful to understand feather disorders.

Feather disorders (especially feather picking) can be one of the most frustrating and disconcerting conditions of caged birds to owners as well as their veterinarians. The list of factors contributing to feather problems or feather picking is long and extensive. For example, poor feather condition can be related to improper environment or diet, trauma, hormonal and reproductive diseases, psychological, metabolic diseases, genetic, viruses, bacteria, fungi, as well as internal and external parasites. The frustrating part of feather disorders is that many of the conditions look identical. This makes the diagnostic workup by the veterinarian difficult. Contrary to popular opinion, external parasites (mites, in particular), are extremely rare among caged birds.

Close observation of the feathers and skin can sometimes give insight to the cause of poor feather appearance. For example, broken and ragged feathers could be due to improper housing, mate trauma, or delayed molt. Brittle and frazzled feathers with scaly skin is often a sign of poor nutrition. Stress marks (horizontal lines of improper feather growth) are a sign that when the feather was in the "pin" stage, the bird was ill or stressed. Retarded feather growth and retention of pin feather sheaths in young birds can be due to a dry environment. Abnormal coloration can be genetic, diet, or internal illness. 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. If this is accompanied by puritis (itchy skin), it can indicate extreme environmental temperature fluctuations, low thyroid function or internal parasites such as giardia.

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. This is thought to be related to trauma to the follicle (the base of the feather) and in cannaries it is a genetic problem. 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. In budgies they're call "creepers" but it has been reported in cockatiels as well.

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. There is feather loss or damage below the neck and the head feathers are spared and appear healthy. The only exception to this is if the cage mate picks the head feathers of the "victim". Causes for feather picking conditions in cockatiels are allergic and parasitic. The most notorious is giardia. Giardia is theorized to cause a malabsorption of needed vitamins and nutrients compounded by an allergic response to the parasite. This combination is responsible for the severe puritis that cockatiels get. The areas most frequently picked at are the wrist, shoulder, flank, and breast. At times the feather picking can get so intense the bird will mutilate it's own body. Some birds can show a hypersensitivity to bacteria and fungi on the skin which can cause a bird to pick and mutilate it's skin as well.