Birdhouse

One of the saddest problems seen in avian medicine is feather damaging behaviour (also known as feather picking, feather plucking or feather chewing). It is sad for several reasons. Firstly, it is a ‘disease’ of captivity— such behaviour is obviously incompatible with survival in the wild—and secondly, it is a problem that is  difficult to cure in that it can often be controlled, but rarely cured.

Knowing that human interaction with
birds has caused this problem and that we can’t cure it can be both
frustrating and demoralising.
Self-inflicted feather damaging behaviour is one of the most
common and most frustrating conditions that veterinarians can be
presented with. The causes for this condition are often multi-factorial
and cascading in their effects. By the time the bird is presented to the
clinician the original inciting cause may have disappeared or been
obscured by other complicating or reinforcing factors.
Feather damaging behaviour may be due to either physical or
behavioural problems. It is simplistic and inaccurate to diagnose
‘boredom’ or ‘fear/anxiety’ without a thorough investigation to rule
out physical problems first. It is also simplistic to feel that a single
cause exists for each individual case. In many cases several factors,
both physical and behavioural, have combined to produce the
clinical sign of feather damaging behaviour.

PHYSICAL CAUSES OF FEATHER DAMAGING
BEHAVIOUR

Anything that makes a bird’s skin itchy or painful can result in feather
damaging behaviour.
Parasites both external (mites, lice) and internal (Giardia) are
over-diagnosed as a cause of feather damaging behaviour. Pet
shops and some breeders often advise bird owners to treat birds
exhibiting feather damaging behaviour for lice. Giardia has only
been associated with feather damaging behaviour in Cockatiels yet
many case studies report Giardia testing in non-Cockatiel species.
Pet birds in particular are rarely affected by parasites. In reality,
parasites may make a bird itchy, but rarely result in feather loss.
Dermatitis (inflammation of the skin) and folliculitis (inflammation
of the feather follicles) can be due to infections (bacterial, fungal,
viral), chemical irritants (eg nicotine absorbed from the owner’s
fingers) or allergies. It is still unproven that birds can develop
allergies but there is strong evidence that they may be a factor in
some feather pickers.
Malnutrition especially caused by an all-seed diet often results
in dry, flaky skin that is predisposed to superficial infections with
resultant itchiness. Feathers will also become brittle and subject to
breakage which may stimulate a bird to chew at them.
Heavy metal poisoning is often implicated as a cause of feather
damaging behaviour. However, all reported cases are anecdotal
and there is no reliable evidence that it causes feather damaging
behaviour.
Underlying painful lesions in the muscles, bones or internal organs
can cause a bird to pick at the skin and feathers overlying the painful
area.
Reproductive activity perhaps through ovarian and oviductal
enlargement and liver changes (vitellogenesis—mobilisation of fat
from the liver to form egg yolks) is believed to cause abdominal
discomfort that may be seen as feather damaging behaviour of the
thighs and ventral abdomen of some reproductively active hens.
There are also some species specific conditions that can be seen
as feather-picking self-mutilation.
Polyfolliculosis is a chronic condition that can cause multiple small
feather cysts in Budgerigars and lovebirds and is often characterised
by intense itchiness. Newly emerging feathers have short, stout quills
with retained sheaths from which several feathers emerge out of a
single, enlarged follicle. There is some discussion as to whether this
condition is the cause of the bird’s intense itchiness or is the result of
damage done by the bird in response to the itch.
Self-mutilation in African lovebirds (Agapornis species) is an
intensely itchy self-mutilation problem affecting the shoulder region
and wing membrane of these small parrots. Less commonly it can
involve the bird’s groin, chest, back, base of the tail and around
the cloaca. At this stage the cause remains unknown. Treatment is
often unrewarding. Placing an Elizabethan collar on until the skin
wounds have healed can be of benefit but recurrence once the collar
is removed is common. Long-term scarring of the wing membrane
often restricts the bird’s ability to fly and the affected area often
cracks and bleeds when the bird stretches its wings.
Cockatiel feather mutilation syndrome is associated with
intestinal giardiasis and has been reported in Cockatiels only. It
appears to be less common now than 10 years ago. It is thought that
the giardiasis causes an intestinal malabsorption syndrome leading
to a vitamin E/selenium deficiency which in turn leads to dry, flaky
skin which can progress to episodes of feather pulling, feather loss
and itchiness. Other clinical signs include weight loss, depression,
ruffled feathers, chronic diarrhoea, neonatal mortality, and weakness.
Treating the Giardia is usually effective.
Quaker Mutilation Syndrome observed occasionally in Quaker
Parrots is seen as an acute onset of severe self-induced skin trauma
which is often directed at the neck and chest and usually unrelated to
prior episodes of feather damaging behaviour. Its cause is uncertain
and treatment can be difficult as the amount of self-inflicted damage
occurring in a short period of time can be overwhelming.

Author:
Dr Bob Doneley
BVSc FACVSc (Avian Health)

The full article you can read by purchasing
Australian Birdkeeper magazine Vol 24 Iss 8 from
www.birdkeeper.com.au
Reproduced with permission from ABK Publications
and Australian BirdKeeper ©2011