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Birds normally molt all their feathers each year, gradually so that flight and insulation functions are not disturbed. The feather loss does not normally result in visible patches of down or bare skin. Feathers grow in tracts with apteria (feather follicle-free areas) between them. Sometimes when a bird has had a bath or if a bird is obese the apteria may become visible. In very active or young birds broken tips of primary wing and tail feathers may be seen as normal wear and tear. Any other form of feather loss or feather damage should be investigated. Self-mutilation should be suspected anytime there is a wound in a relatively protected area, such as the wing web, under the wing, inside the groin area. Injury from a cagemate would be considered if the wound was in an area the bird itself could not reach or in an area where a cagemate would likely attack such as toes, head, and metacarpal areas. Feather picking, damaging, and self-mutila-tion are extremely common in pet birds.

Most avian veterinarians will say that at least 60% of their caseload presents with one of those complaints. There are many, many causes and treatments for these problems. It requires patience and dedication from both the veterinarian and the owner to help most of these birds. Owners need to understand from the beginning that finding the cause and the treatment may require a great deal of detective work and trial and error. It is tempting for them to give up when a solution isn’t found quickly, so they need to be prepared for the possibility that it might take months to find a solution or solutions.

Some feather pickers, damagers, or self-mutila-tors present with a history of normal preening behavior, the owner never seeing the bird do the damage, or they see the birds preen calmly and methodically but do damage instead of leave everything intact. Some birds present with a history of agitated, aggressive preening behavior, “digging” at themselves, stopping normal activities mid-stride to vigorously chew at a feather or their skin, or in other ways acting irritated or irritable (foot stomping or shaking, screaming). Some birds present with an unclear history.
All feather pickers, damagers, and self-mutilators should be tested for potential organic causes of the behavior because histories and birds’ behavior can be misleading, but the birds that definitely act pruritic or that possibly act pruritic should be very carefully investigated. If test results are negative these birds should not be assumed to be behavioral feather pickers, although that may be a component of their problem. In the testing of Roudybush Rice Diet a few birds described as pruritic by the owner stopped showing pruritic behavior but continued to feather pick at a reduced level.

Behavioral/Emotional: There are many behavioral or emotional causes for feather picking, damaging, and self-mutilating. Behavioral causes are high on the list of differentials when the preening behavior is non-pruritic or if the owner never sees the behavior. Boredom, desire to breed, territorial conflicts, stress from “flock” (human, bird, other pet) interactions, stress from environmental conditions, changes in schedule or environment, and sleep deprivation have all been described as behavioral or emotional causes. It has also been suggested that captive birds have much more time for preening because their food and water needs are so readily met.
Viral: Feather loss may be seen with Psittacine Beak and Feather Disease (PBFD, Circovirus 1) or polyomavirus. Feather loss is usually gradually progressive, symmetrical, and non-pruritic. Beak lesions are often not seen with PBFD. Circovirus 2, affecting lories and lorikeets, usually causes abnormal feathercoloration but not feather loss. If a bird is infected with Circovirus 1 or polyomavirus and is losing feathers, it is not reversible. The bird needs to be isolated from other birds or euthanized.
Bacterial: Bacterial dermatitis or folliculitis can cause both feather loss and pruritic feather picking, feather damaging, or self-mutilation. Both gram positive and gram negative organisms have been implicated.
Fungal: Fungal dermatitis or folliculitis can cause both feather loss and pruritis. There also appears to be hypersensitivity or allergic reactions to fungal infections of the respiratory and GI tracts. Some birds with Aspergillosis, for example, will start to self-mutilate before they start showing clinical signs of fungal pneumonia or air sacculitis. Some birds become pruritic when Candida spp. overgrow in their intestinal tract. Treatment for the yeast relieves the pruritis. It is possible that inhaled allergies to fungal spores in the environment will be determined to be one of the causes of feather and skin damaging disorders.
Parasitic: Knemidocoptes infection can result in feather loss, especially in the facial, vent, and leg areas. It may also cause some birds to show pruritis. Other external parasites, feather mites and lice, can cause irritation and feather picking and damaging behavior. Internal parasites, especially Giardia, can cause feather picking and damaging and self-mutilation behavior.
Chronic Diseases: Neoplasia or benign tumors can cause self-mutilation or feather picking in the area affected. Feather cysts, uropygial gland infections, cysts, or tumors can result in self-mutilation or feather picking in the area affected. Kidney disease, liver disease, and pancreatic disease should be considered.
Toxic: Exposure to inhaled or contact toxins or irritants can cause feather picking, damaging and self-mutilation. Common offending toxins or irritants are cigarette smoke, aerosols, cleaning products, personal hygiene products, laundry products, petroleum products, and topical ointments.

Allergic: Allergy testing is still not validated for avian species. Research is ongoing, but currently there are no standardized methods to test for allergies in birds. Because we cannot conclusively determine if a bird is allergic to something, some people are reluctant to include allergies as a cause of feather picking, damaging, and self-mutilation. It is difficult to defend a position that birds can’t have allergies, however. When other causes of these behaviors have been ruled out, certainly allergies should be considered. Any substance that is known to be an allergen in other species should be considered as a potential allergen in birds.

Each case should be worked up individually. Having a standard “Feather Picker Workup” can be misleading. Start with a good history. Every aspect of the bird’s lifestyle, diet, immediate environment, “flock” interactions, schedule and behavioral history should be investigated. If possible, the bird’s cage and immediate environment should be visualized in person or via photo. Determine if anything changed within a month of the start of the abnormal behavior. Try to determine from the owner’s description, your own observations, or photographic documentation if the bird seems pruritic. A very detailed history is especially important in behavioral/emotional and toxic/irritant caused cases. Viral etiologies can be investigated using DNA probes. History and clinical presentation can help determine if viral causes are likely. Bacterial and fungal causes can be diagnosed by gram stains of skin scrapings, feather pulp, crop,
vent, and fresh fecal smears. Aerobic cultures and fungal cultures of feather pulp or skin scrapings can be performed. Biopsies sometimes show colonization with organisms. Biopsies should be paired, one from an unaffected area, one from an affected area, to help differentiate secondary skin changes. External parasites, tumors, cysts or other superficial abnormalities can be diagnosed through physical examination. Sometimes having the client cover their bird’s cage with a white sheet helps to diagnose feather mites. Fresh fecal smears can be examined for yeasts and internal parasites. A CBC and serum chemistry panel, including bile acids, should be performed to rule in or rule out chronic diseases. Allergies or hypersensitivity should be considered if the above test results are negative, if the CBC shows an elevated basophil count, especially if the bird shows evidence of pruritis. Although
the function of the basophil is not completely understood, it has been shown to be involved in early inflammation and hypersensitivity reactions in birds. However, a normal basophil count does not rule out an allergy or hypersensitivity. The only diagnostic test available for allergies in birds at this time is the use of an elimination diet to diagnose food allergies or adverse food reactions. This test should be used with birds that are constantly pruritic or with birds where it is not determined if they are pruritic. Birds that are seasonally pruritic or seasonal in their abnormal behavior are not likely to have food allergies or
adverse food reactions unless their diet is changing to coincide with the ebb and flow of their clinical signs.

Roudybush Rice Diet is an elimination diet that derives all its proteins (therefore, potential allergens) from rice. Although rice is occasionally fed to some birds as a treat, it isn’t a common or integral part of the diet of most pet birds. It will very often be a novel protein for the bird. The diet is formulated as a normal maintenance diet, so there are no concerns about nutritional adequacy during the test period, and if the bird does improve, it can be maintained on the Rice Diet as a treatment. Testing of the diet since 2001 indicates that the diet is very well accepted by most birds. Once other causes of a bird’s feather picking, damaging, or self-mutilation have been ruled out, the bird may be put on the Rice Diet as a diagnostic test for food allergies or adverse food reactions. Client compliance is of the utmost importance with an elimination diet. Every member of the household must understand the importance of avoiding exposure to any other food item during the test period. They should be encouraged to keep a journal of their bird’s behavior. They should understand that allergic responses can take a week or two to show up or to disappear, so additions and subtractions from the diet need to be done singly and slowly. Roudybush provides a client education handout that describes the elimination diet protocol. Basically, once a bird has been successfully converted to the Rice Diet they should have nothing but Rice Diet and rice-only treats until their bird’s abnormal behavior decreases to its minimum or ceases. They may then add one simple food item back into the diet and observe the results for two weeks. If the bird continues to do well, they can add another simple food item, and so on. If the bird reverts to abnormal behavior, they must remove the offending food item and wait until the bird is back to its most normal behavior before trying a different simple food item. If the bird is not showing improvement, continue the Rice Diet for a minimum of 10 weeks before concluding the test. Some birds have been found to respond slowly and require this time frame to show improvement. In over two years of testing prior to marketing the Rice Diet, out of 24 birds placed on the Rice Diet 7/24 showed complete resolution of abnormal behavior. Another 8/24 birds showed partial resolution of abnormal behavior (estimated at 25–95% resolution by owners). Nine birds showed no improvement.

There are several ways an owner can convert their bird to Roudybush Rice Diet. The quickest way to start the test is a controlled cold turkey method. The owner replaces the old food with the Rice Diet (after making sure all food bowls are thoroughly cleaned to prevent contamination with dust from the old food). Have the owner clean the cage at the time of the switch and use paper instead of litter at the bottom of the cage. The owner watches the bird’s droppings for evidence of anorexia—small, dark feces or urine and urates only. As a bird begins to eat the Rice Diet their droppings become a light green. If the bird shows anorexic droppings at the end of the second day for birds less than 250 grams or by the end of the third day for birds greater than 250
grams, the owner gives the bird its old food back for a week and then attempts the switch again. A more careful but potentially prolonged method of conversion is to place a food dish with Rice Diet in a preferred eating spot in the cage (usually a high position) with a water dish or bottle close by. Put a dish of the old diet in a portion of the cage that the bird doesn’t usually frequent (usually a very low position) with no water in the area. Most birds will tire of going to the awkwardly placed feeder and will choose to eat the food in the preferred position. Once the owner is sure the bird is eating the Rice Diet, remove the old food, change the cage papers and observe the droppings to be sure the bird is eating. The Rice Diet can be added gradually to the existing
diet for birds that accept new foods readily. The owner increases the proportion of Rice Diet every few days and watches the droppings closely when they reach the point of giving nothing but Rice Diet. They need to thoroughly clean the feeder at this point to make sure no dust from the previous diet contaminates the Rice Diet. Once the bird is eating nothing but the Rice Diet it can have rice-only treats. The owner should be advised that white rice, brown rice, rice cakes, rice noodles are all acceptable to use as treats, but they should look at ingredient lists and be sure there are no ingredients from corn, soy, wheat, etc. Even if the food item contains corn oil or cornstarch it should not be given to the bird during the test period.