Parrots and Premature Handling
09 January 2004
Writing in this week's Veterinary Record (January 10, pages 42-48), Mr Harcourt-Brown suggests that premature handling by humans is a factor behind the high incidence of the bone disorder, juvenile osteodystrophy, in parrots kept in captivity. A survey he carried out last year showed that nearly half the hand-reared African grey parrots examined in his practice had some degree of deformity, particularly in the tibiotarsus bones of the legs.
It has long been known by vets that unsatisfactory diets are often the cause of bone disease in parrots but he found that problems were occurring in birds receiving adequate amounts of calcium and vitamin D. So he set out to discover what other factors may be involved by studying the early development of the skeletons of dusky parrots (Pionus fuscus), a South American species that he has kept and bred successfully in his own aviary for many years.
At his practice in Harrogate, Mr Harcourt-Brown took radiographs of each member of a clutch of five dusky parrots at regular intervals from 16 to 45 days after hatching. While preparing the chicks for the X-ray table he realised why hand rearing is more likely to cause the development of bone abnormalities than naturally breeding.
Huddled together in the confined space of a nest, chicks are unable to move much before they are about 50 days old when they begin to flap their wings. But a chick removed from the nest and put on a flat table top will try to stand up and move about until it is reunited with its nest mates. Mr Harcourt Brown's X-rays showed that the leg bones are clearly too weak to support the bird's weight until they are about 40 days old.
"Hand rearing encourages abnormal physical behaviour in growing parrots that may exacerbate the effects of a deficient diet and encourages the development of skeletal deformity. In some birds with mild signs of juvenile dystrophy it is possible that over-exercise is a major factor in the development of their bone deformity," he says.
However, bone disorders are not the only health problem linked to hand rearing. Mr Harcourt-Brown points out that feather plucking and other acts of self mutilation are much more common in hand reared birds than in either parrots reared by their parents in captivity or wild caught birds. He says this is caused by the frustration that arises in birds that have been reared to believe that they are humans but which retain the behavioural programming of their wild ancestors.
Mr Harcourt Brown says he would not want to discourage breeders from hand rearing birds but says they must modify the way they manage their birds to ensure that they grow up physically and mentally healthy. Already some breeders have discovered how to produce hand-reared parrots that behave normally and yet "know they are still parrots" by rearing them in the company of tame adolescent birds. Alternatively, chicks left in the care of their natural parents can develop into good pets as long as they have regular contact with humans from an early age, he says.
With hand-reared birds costing up to £800 each, breeders have a duty of care to ensure that the birds they offer for sale are physically sound, he says. "Hand rearing doesn't always mean that the birds are going to develop problems - but some species like the African grey breed so readily that if they are not looked after properly then there are likely to be serious problems. Parrot breeders should have some of their young birds examined by a vet, with X-rays taken to show that they have normal bones."
Notes for Editors:
- For further information please contact Chrissie Nicholls or Helena Cotton in the BVA Press Office on 020 7636 6541 or email chrissien@bva.co.uk.