Feather Plucking

Introduction

Feather-plucking is a common presenting sign in birds. Underlying causes are often multifactorial, so diagnosis and treatment of several of the contributing factors may be necessary to produce resolution of clinical signs. It is best to rule out medical causes before diagnosing the feather-plucking as behavioral in origin, therefore a thorough work-up is indicated including a detailed history, physical and dermatological exam. Referral may be considered.

Individual tests such as; haemotology, biochemistry, heavy metal testing, sexing, skin acetates, pulp cytology and faecal staining should all be performed in the initial work up to guide diagnosis. Additional tests that should be considered are; Chlamydophila testing, circovirus testing, coeloscopy, radiography, skin biopsy, crop biopsy and faecal flotation (for Giardia and other helminths).

The causes of feather-plucking can be divided up into three categories:

(1) Infectious, contagious or transmissible causes

(2) Non-infectious and metabolic cause

(3) Psychological causes

Infectious, contagious or transmissible causes of feather plucking

• PBFD (circovirus)
• Budgerigar fledgeling disease (Polyomavirus: French moult)
• Ectoparasites (e.g. Dermanyssus gallinae)
• Endoparasites (e.g. Giardia sp.)
• Chlamydiosis
• Fungal dermatitis

Diagnosis

PCR for PBFD and BFD; physical examination at day and night for ectoparasites; faecal examination for endoparasites; PCR/ELISA (antigen/antibody) for chlamydiosis; skin scrape microscopic examination and culture for fungal dermatitis; stained impression smear, culture and sensitivity for bacterial infections. Also, haematology and biochemistry, thyroid stimulation test, biopsy and histopathology, improved diet and monitoring response to therapy.

Treatment

Treatment is dependent on the individual underlying infection.

Non-infectious and metabolic causes of feather plucking

• Bacterial dermatitis
• Pulpitis or folliculitis
• Allergy
• Hepatitis
• Hypothyroidism
• Skin neoplasia
• Follicular cysts
• Post-traumatic injury, or arthritic or scar tissue pain
• Nutritional deficiency (e.g. hypovitaminosis A; B vitamin deficiencies) and essential amino acid deficiencies (e.g. lysine))

Diagnosis

This should be based on a combination of history, clinical signs and the results of preliminary and secondary test results as mentioned above.

Treatment

Treatment is dependant on the individual underlying cause.

Psychological causes of feather plucking

• Attention seeking
• Boredom and separation anxiety
• Overcrowding
• Environmental change or lack of routine
• Sexual frustration
• Excessive preening
• Post untidy feather or wing clipping.

Diagnosis

The psychological plucker presents as a clinically normal bird in all respects except for its plumage. Bacterial, fungal, parasitic, viral, chlamydial and metabolic aetiologies for feather plucking should be ruled out. The feathers on the head are totally normal (if head feathers are affected disease is most likely caused by an circovirus, bacterial or yeast infection). It is most common in hand-reared birds and plucking is often only done in the presence of the owner.

Reproductive hormonal pressure aka sexual frustration is the most common cause of psychological feather-plucking. It often begins to cause picking in young birds that are bonded to their owner even before reaching what is thought to be natural reproductive age. The hormonal drive provides a natural incentive for the young bird to try to achieve a status in the dominance hierarchy of the flock. This will lead to success in obtaining a mate, holding territory and having access to adequate food, so that it is able to reproduce. Captive birds often mature earlier than wild birds, especially when the owner is providing all the necessary advantages as well as stimulating it with a close bond. Consequently the bird reaches reproductive maturity but the ‘mate’ is not responding in the manner that will result in the production of offspring. This often leads to ‘displacement behaviour’ such as feather picking, screaming or aggression.

Treatment

Attention seeking should be discouraged by the owner by ignoring the bird when it is feather plucking, and then fussing it when it has stopped. Gradually the bird should learn not to feather pluck.

Boredom and separation anxiety should be managed by providing various bird toys and encouraging independent play. Ideally the bird should be tired out by activities such as bathing and play prior to the owner leaving the house. Leaving on a radio or television may also help with separation anxiety.

Overcrowding should clearly be managed by reducing the number of birds per cage, or providing the bird with a larger cage.

Over-preening is considered a type of obsessive-compulsive behavior. To counteract this, the bird should be encouraged to play independently and any objects it may be scared of should be removed. The cage may also require re-positioning. As for attention-seeking, the behavior should not be encouraged. Anti-compulsive medication may be used.

For birds suffering from reproductive hormonal pressure, some success has been achieved with the administration of progesterones to decrease the hormonal pressurein sexually frustrated birds but some treated birds become obese, suffer from polyuria/polydipsia, diabetes mellitus or develop hepatic lipidosis. Recently, human chorionic gonadotrophin (HCG) (500–1000 IU kg-1 i.m.) has shown promise in providing effective, short-term resolution, especially in African grey parrots and cockatoo hens. There have been no reports of adverse reactions with this treatment but it is not always reliable. Tranquillizing agents – such as haloperidol – and psychotropic agents – such as clomipramine and Prozac – have shown some limited effectiveness in some individual cases. These medications can only provide a temporary solution and should be used in combination with behaviour modification techniques and changes in the bird’s environment to provide a more reliable response. Petting on the bird’s back and intimate cuddling should be reduced or eliminated. For the owner to assert dominance the bird should be maintained below human chest height. The cage may be moved to a location away from the main traffic area to reduce the anxiety of seeing the owner without being cuddled. The length of the day may be shortened by covering the cage earlier in the evening and, in the case of females, surgical removal of the oviduct may provide the best long-term solution. In some cases, the picking becomes a habit, even though the original cause is resolved and long-term, anti-compulsive medication may be indicated.

References

Forbes NA & Altman RB (1998) Self-Assessment Colour Review Avian Medicine Manson Publishing Ltd

Chitty, J (2003) Feather plucking in psittacine birds 1. Presentation and medical investigation In Practice 2003 25: 484-493

Chitty, J (2003) Feather plucking in psittacine birds 2. Social, environmental and behavioural considerations In Practice 2003 25: 550-55