There are both medical and non-medical causes for feather picking. The major medical causes include changes in hormone levels, external and internal parasites, malnutrition, internal disease, and bacterial or fungal infections of the skin and/or feather follicles. Interestingly, and con” to popular opinion, external parasites (mites in particular) are extremely rare among caged birds. The non medical causes are psychologic and/or stress related.
Infection with the 1-celled intestinal parasite, Giardia, may be related to feather picking. Many birds with giardiasis, especially parakeets, cockatiels and some lovebirds, also show intense feather pulling, self-mutilation and loud screaming Giardiasis is diagnosed by microscopic fecal examination. Treatment is difficult and may be unsuccessful. Further, giardiasis, can be transmitted to people.
Feather picking is generally a problem of birds in captivity. Wild birds do not feather pick because they are too preoccupied with their own survival and with reproduction. Captive birds (pet birds and those in zoos and avicultural collections) endure stress not experienced by their wild counterparts. Captivity, malnutrition, solitary living, absence of a mate with which to fulfill courtship rituals and mating needs cause significant stress, in addition to stress associated with confinement within a home (noise, confusion, presence of other pets, such as dogs or cats, which represent potential predators to caged birds).
Inadequate feather care & maintenance
Normal feather care & maintenance
Obsessive, excessive damage to feathers
Like people, birds are creatures of habit, and changes large or small) in their environment or in their established routine can often create stress for the individual. This stress often results in obsessive, introverted behavior, manifested by feather picking.
It is helpful to understand that feather picking represents one extreme of the feather care and maintenance continuum, as illustrated in the diagram.
In the middle of this continuum is normal feather care and maintenance, represented by normal preening. To the left is the complete absence of feather care and maintenance, most commonly seen with domestic, hand-raised birds. These baby birds fail to learn proper preening (technique and frequency) from their parents. To the right of the middle is overzealous preening or outright damage to, or destruction of, the plumage represented by feather picking.
Bird behavior tends to be patterned and ritualized. With this fact and the feather care and maintenance continuum in mind, it should not be too difficult to appreciate why captive birds, experiencing multiple stresses day after day, continuously pick at their feathers. There is little difference between drawing a feather through the beak to condition it (preening) and doing the same thing but clamping down on the feather midway through the process and cutting it in half or pulling it out (feather picking).
Most caged birds seem prone to feather picking. The groups of birds most notorious for engaging in this vice include African gray and Timneh parrots, cockatoos, macaws, conures, gray-cheeked parakeets, and cockatiels. Interestingly, we rarely see feather-picking budgies or Amazon parrots. We do, however, see a self-mutilation syndrome in Amazon parrots and occasionally in other species (African gray parrots, macaws). This may represent the way in which some of these birds cope with or manifest stress. It is not uncommon for afflicted birds to mutilate their skin (toes, wing webs, groin and armpit areas). This constant and continual trauma results in infection and failure of these wounded areas to heal. These birds must be prevented from engaging in this self-trauma through use of collars, bandages, etc. They also must be treated aggressively with systemic antibiotics (injections are preferable).
Some veterinarians believe that self-mutilation is caused by an infection, possibly a viral infection. A pox virus is thought to cause chronic skin ulcers, especially in lovebirds. Skin biopsies are required for diagnosis. A vaccine is now available for prevention of pox in parrots and related birds.
Birds with feather picking should undergo a thorough physical examination and laboratory evaluation to determine the underlying cause.