Feather picking (self-mutilation syndrome)

In birds, the care and cleaning of feathers is an extremely important activity that occupies a lot of time. When these activities become pathological they can result in acts of self-mutilation (feather damaging or picking, lesions to the skin or even to the underlying muscles).

Self-inflictedfeather picking is a common disorder in avian medicine; the aetiology is multifactorial and is at times quite complex and not easily identifiable. The conditionis difficult to treat and is often frustrating for both the veterinarian and the owner. In this regard, good communication is important and it is essential in to inform the owner about the possible diagnostic and therapeutic complexity and of the possibility of not being able to correct the problem. As a rule, a reduction in the self-mutilating behaviour is to be considered a success; the complete resolution of the phenomenon is rare. 

Curiously, the syndrome has never been reported in free roaming psittacines; it is therefore a disorder of captive individuals. The most common mistake done when treating this condition is to automatically assume that the problem is strictly behavioural, without investigating other possible causes.

The most frequently affected species are: cockatoos, African greys, Amazon parrots, macaws, Eclectus parrots, conures, cockatiels and lovebirds.

When dealing with a bird with feather problems it is first necessary to establish if it is indeed a problem of self-mutilation and not a case of spontaneous feather loss or lack of growth. In case of self-mutilation, the areas not reachable by the bird’s beak - meaning the head - are spared; in the rest of the body the feathers are either missing (Figs. 1-3) or damaged by the beak (broken or with damaged barbs, Fig. 4).

It is always necessary to exclude the possibility that a cage companion may have been the cause of the mutilation.

The owner is sometimes not aware that the problem is caused by the bird itself and simply reports that the animal is loosing its feathers. Even in cases of obvious feather chewing the owner may still feel that the feather loss is caused by a disease and not by self-mutilation. Moreover, in many cases owners cannot distinguish between a normal cleaning behaviour and feather plucking.

The differentiation between feather picking and feather chewing is useful as in the second case a behavioural disorder is more likely the cause.

It is then necessary to try to identify the cause (or causes) of feather picking. However, patients are often seen months or even years after the beginning of the problem; at the time of presentation the triggering cause may no longer be present and hence may not be identified.

The collection of an accurate clinical history may allow to detect how the problem started and how it evolved; it allows to establish the diet used, the housing method, the eventual presence of toxic substances in the environment (such as cigarette smoke), the time spent by the bird alone or in company, eventual changes in the environment, etc.

A dermatological examination is necessary to assess the distribution of the lesions, the type of damage to the feathers (which can be completely plucked, or broken, or with the barbs chewed and the quill intact). The skin must be examined in order to identify the presence of lesions (erythema, excoriations, crusting, hyperkeratosis, etc.) or of parasites. The taking of pictures is particularly useful in order to document the current extent of the lesions and to assess any eventual improvement.

Collateral investigations are necessary to eventually confirm the presence of a condition responsible for this abnormal behaviour. Diseases not directly related to feather picking must also be identified and corrected, as they can be the cause of pain or stress, which may favour the skin problem. The selection of tests to be performed is guided by the information resulting from the clinical history and physical examination. The basic minimum assessment includes a complete blood count, clinical chemistry tests with protein electrophoresis and fresh stools and faecal flotation tests for the detection of intestinal parasites. Internal organ diseases (liver, kidney, bowel, etc.) may also be correlated with feather picking. Based on the initial clinical assessment it may be decided to either start immediately with other tests or to await the outcome of the first tests and then use them as a guide for the subsequent ones.

Other potentially useful tests include: cytology, skin biopsy, bacteriological examination, X-rays, measurement of heavy metal levels, virological tests (PBFD, polyomavirus), chlamydia test, evaluation of thyroid function.

Should all the medical tests not prove the presence of any disease, or should the treatment of any disease present not solve the problem, a diagnosis of behavioural disorder can be made.

AETIOLOGY AND TREATMENT OF FEATHER PICKING

PHYSICAL CAUSES

Internal parasites

Giardia intestinalismay be associated with feather picking in cockatiels; the underlying mechanism is believed to be attributable to an allergic reaction to the parasite that causes skin pruritus. The plucking starts at the level of the carpus-metacarpus, hips and hind limbs. The picking may be the only symptom associated with giardiasis; as faecal shedding of the parasite is often sporadic, should giardiasis be suspected - even in the presence of a negative faecal test – a treatment attempt can be made with metronidazole,.

Feather picking has also been correlated with the presence of other intestinal and blood parasites.

External parasites

The role of external parasites (mites and lice) as a potential cause of feather picking is usually overemphasized, especially by the owners. Parasites are easily visible and therefore easily identifiable. When in doubt, an antiparasitic drug may be used (e.g., pyrethrum spray or fipronil applied with a cotton swab on the feather-less skin under the wings) and the results monitored.

Allergic reactions

Some preliminary studies indicate that in birds, allergic reactions are possible, and that these manifest themselves with skin pruritus and then with self-mutilation. Both food and environmental allergens are suspected. Some cases of feather picking do in fact respond to the administration of glucocorticoids or antihistamines. The study of intradermal tests for the diagnosis and treatment of skin allergies is currently under examination in psittaciformes.

If an allergic problem is suspected, an attempt may be made to reduce or eliminate exposure to the antigen, following the same principles used in dogs and cats (and in people). For airborne allergens (pollens, dust), meticulous cleaning, frequent airing and the avoidance of cigarette smoke in the environment in which the parrot is housed are useful. In the case of food allergens, an elimination diet may be tried using high-quality pelletized feed, free of preservatives and dyes.

Should such measures not be successful, an attempt can be made with antihistamines (i.e. diphenhydramine), tricyclic antidepressants (which also have an antihistaminic action) and omega-3 fatty acids. Steroids are to be avoided in view of their potential side effects; in addition, they typically do not control the itching adequately.

Environmental irritants

Anecdotally, contact with substances such as home fragrances, cigarette smoke, hairspray, deodorant sprays, lotions and hand creams has been correlated with feather picking. As a precaution, all these substances should be avoided.

Diseases of internal organs

It is documented that skin pruritus may be present in birds suffering from liver disease, which in turn manifests itself with feather picking. In practice, any disorder of internal organs (including poisoning by heavy metals and cancer) may be the cause of a feeling of discomfort that may result in feather picking or self-mutilation. The use of collateral examinations in order to assess the overall status of the animal is therefore important.

Infectious skin diseases

The skin of birds is believed to be relatively resistant to bacterial infections; however, in the presence of feather picking, these - and in particular feather follicle infections - must be excluded. Bacterial and fungal infections may be the cause or the consequence of feather picking. In either case, an appropriate therapy must be implemented.

In feather-picking parrots, tests for PBFD and for polyomavirus infection may be indicated.

In psittacines, Malassezia skin infections are possible. The best way to diagnose a Malassezia infection is not by culture or biopsy, but with cytology. The glass slide is pressed against the skin and is then heat-fixed and stained. In the presence of a Malassezia skin infection, the resolution of feather picking has been obtained with the administration of fluconazole at a dose of 2-5 mg/kg, nebulization of clotrimazole at (10%) and spraying with diluted vinegar.

A large number of fungi detectable with cytology may also be found in clinically healthy birds.

Dietary deficiencies

An unbalanced diet, with severe deficiencies, is very common in birds in captivity (typical is the case of seed-only diets, sometimes "supplemented" with a piece of apple and a leaf of lettuce). Some believe that the plucking of feathers in the presence of a dietary deficiency may be a form of pica, an attempt to ingest animal protein not supplied with the diet. However, the mechanisms by which a dietary deficiency may induce feather picking are not yet fully clarified, also because not all pet parrots with inappropriate diets (the vast majority) develop problems of self-mutilation. In all cases, a balanced diet is essential for the animal. In practice, some cases of feather picking simply respond to the use of a proper diet, exposure to fresh air and direct sunlight, as well as to regular bathings.

Trimming of flight feathers

The trimming of flight feathers may be the cause of self-mutilation, by way of various mechanisms, especially if the trimming is not done properly. Flight feather trimming may make the parrot unsecure, taking away one of its basic skills, i.e. flight (Fig. 5). Cut quills may be the cause of discomfort, causing the bird to chew them (Fig. 6). If the trimming is performed incorrectly (on one wing only, in order to unbalance flight), the animal may fall and injure itself, traumatizing the feathers of the affected area (Fig. 7).

PHSYCOLOGICAL CAUSES

As already mentioned, feather picking of behavioural origin cannot be diagnosed without having first performed a series of medical examinations, which must have given negative results.

The birds more prone to feather picking of behavioural origin are the African grays, cockatoos and conures; in cockatiels and parakeets the problem is more likely of physical origin.

When a "psychological" disorder is suspected, the behavioural and environmental history must be collected and analysed in detail, in the attempt of identifying the underlying aetiology, which is necessary to establish a proper behavioural and/or pharmacologic therapy. Overlapping problems are often present, which may manifest themselves with identical symptoms. Behavioural therapy requires identifying the cause or causes that trigger the behaviour to be avoided (in this case the plucking of feathers), removing such causes - if possible -, and replacing the unwelcome behaviour with other acceptable ones.

Possible causes include: boredom, stress, fear (of other animals or people), loneliness, sexual frustration, attention seeking. Lack of sleep may be a cause: normally, birds need 10-12 hours of sleep; it is unlikely that a parrot staying at home may enjoy a sufficient number of hours of sleep, in the dark and in the quiet, unless in the evening it is not moved to an appropriate area of the house.

Another factor to bear in mind is that feather plucking can trigger the release of endorphins, which give a feeling of pleasure and can be addictive, perpetuating the harmful behaviour. Once started, the plucking can become a habit, and continue even if the triggering cause has disappeared. Sometimes, the damage to the follicle is so severe that the feather is no longer able to grow back, even if the initial problem has been solved.

In the case of loneliness and boredom the bird lingers with self-mutilation for lack of adequate stimuli. In such cases, the environment where the animal lives must be enriched with toys, the cage must be placed in an area where the family members are present and physical exercise must be promoted.

In the wild, parrots occupy most of their time searching for food, while in captivity they have easy access to an unlimited amount of highly caloric food. A great method of environmental enrichment and of "occupational therapy" consists in ensuring that the parrot is forced to search for food, spreading it in the environment and partly hiding it, as well as using skill games that require a certain manipulation on the part of the animal to reach the food.

Attention seeking is another frequent aetiology. Parrots are social animals that live in groups; maintaining contact with their own kind is an innate behaviour, and they try to replicate it with their human family. An overlooked parrot will perform any conduct to draw the owner’s attention, including feather picking. In addition, parrots are noisy creatures and love to scream; an agitated human being who screams in front of them in the attempt of making them stop an undesirable behaviour (feather picking) achieves nothing, and in fact increases the animal's enjoyment and reinforces the undesired behaviour. On the contrary, not paying attention to the unwelcome behaviour, and even leaving the room whenever the animal begins to pick its feather, punishes such behaviour, as the bird obtains exactly the opposite effect of the one desired. In addition, positive behaviours must be rewarded, such as when the parrot stands still or plays by itself. A simple prize may consist in talking to the animal with a calm tone, praising it, or giving it some welcome treats.

Other causes of feather picking are fear, sexual frustration, stress (i.e. changes in the environment) or obsessive/compulsive disorders. In some parrots the behaviour may be triggered as a reaction to the loss of a companion, be it human or avian (Fig. 8). This said, the behavioural foundations of feather picking are not yet fully understood and some parrots continue to maintain this kind of behaviour despite undergoing all sorts of behavioural therapy.

To evaluate the effectiveness of any behavioural interventions several weeks are needed. Should acceptable results not be achieved with this approach, a pharmacological intervention may be attempted, bearing in mind that studies in this regard are still scarce, that the dosages are mostly empirical and that these interventions are still to be considered as experimental. In this regard, it is fundamental to obtain the informed consent of the owner.

It is also necessary to provide an adequate diet, varied and balanced, and to allow the bird to bathe, which encourages a proper cleaning behaviour and helps the feathers and skin to remain in good condition.

Table 1. Behavioural aetiology and treatment of feather picking (from K. R. Welle, Clinical Approach to Feather Picking, AAV Proceedings 1999)

Table 2. Drugs used in the treatment of feather picking of psychological origin

Lynne M. Seibert. Psittacine Feather Picking, Western Veterinary Conference 2003

Clomipramine is indicated in the pharmacological treatment of feather picking related to boredom or separation anxiety, when behavioural therapy alone is not effective.

Medroxyprogesterone is indicated for problems related to sexual frustration and excessive attachment to the owner. It can be used in both males and females; it is hypothesized that it may also act via an anti-inflammatory or sedative effect. It can have severe side effects, such as obesity, polyuria/polydipsia and diabetes, so in case of use periodic screening tests are necessary.

In females, the use of HCG is much safer, which induces the production of endogenous progesterone. Its duration of action is however shorter.

Naltrexone works by blocking the effect of endorphins and thus eliminates the positive reinforcement caused by the picking. When plucking its feathers, the bird feels pain instead of pleasure, thus ceasing the destructive behaviour. It is useful in obsessive/compulsive disorders and in stress-related feather picking.

Haloperidol is an antipsychotic tranquillizer effective in some forms of feather picking, with the same indications of naltrexone.

Antidepressants are effective in a small percentage of individuals. In the majority of cases their use is to be considered experimental. In addition, tricyclic antidepressants have an antihistamine, and hence antipruritic, action. 

Containment devices

The use of containment devices to prevent self-mutilation should never be the sole therapeutic approach and should only be used in selected cases, such as when the parrot severely mutilates its skin and underlying tissues. Elizabethan collars may be the cause of severe stress and are not tolerated by all patients; in the first 24 hours, hospitalization may be indicated in order to monitor the reaction of the animal.

Collars can be found on the market or can be custom-made using radiographic film (Fig. 9). In many cases these are more easily accepted by the bird than the cylindrical collars, coated with soft material (Fig. 10); the collars must adhere to the body, in order to prevent the beak from getting stuck into them. In some parrots a sort of a "garment" may be used, made from a sleeve of fabric or from a sock.