Feather damaging behavior (FDB) is a common, frustrating and perplexing disorder, both for the owner and the veterinarian. FDB is not only difficult to diagnose and treat but may be multi-factoral and may require a multifaceted approach for resolution or management. It is important to understand that in many, if not most cases, long term management will be required. For most birds, simple solutions simply don't exist.
At rainforest Clinic for Birds, our approach is to first and foremost try to differentiate between birds which are damaging feathers due to physical causes from those which are psychogenic or hormonal in etiology. It is important however to understand that many cases will have aspects of both physical and psychological causes.
Paired Skin/Feather Biopsies are used to diagnose and differentiate cases of inflammatory skin disease from FDB caused by psychogenic or hormonal disorders. In this procedure the bird is anesthetized and 2 growing feathers and a small section of skin surrounding each is removed to send to a pathologist. One sample is taken from an area of skin where the bird is plucking and another sample is taken from area of skin where the bird is not plucking or cannot reach (usually the head or neck).
The pathologist looks for inflammation around the blood vessels (perivascular inflammation) and the feather follicles (perifollicular inflammation). This is indicated by certain inflammatory cells (Lymphocytes and plasma cells) collecting around these sites. This inflammation causes irritation and itching.
The theory behind paired skin/feather biopsies is simple. If a bird is plucking they usually have inflammation in that area if only due to the trauma of plucking. But if the bird has inflammation in an area where he cannot pluck, this is an indication that he has a systemic inflammatory problem such as an allergy.
We frequently find other problems such as bacterial infections in the follicles, fungal skin infections, nerve inflammation and even iron storage in the skin. If inflammation is not found in the unaffected site, we assume the bird is damaging the feathers because of a psychological problem rather than a physical one.
Other tests may be recommended at the time of the biopsy. Thyroid hormone levels may be tested to detect hypo-thyroids. Blood zinc levels may be tested to detect underlying zinc toxicosis. Sources for zinc toxicosis may include cages, bowls, toys, etc. Zinc toxicosis may need to be treated prior to initiation of anti-inflammatory...