Miscellaneous Diseases

By Edward T. Mallinson.

Bumblefoot, cannibalism, egg binding, feather picking, leg weakness, and various reproductive or anatomic disorders are common to many avian types. Their origins usually stem from a combination of factors, both infectious and noninfectious.

Management (poultry or bird densities, feeding practices, etc.), marginal nutritional deficiencies, recognized and unrecognized infectious agents, and inherited (genetic) weaknesses or predispositions may all be involved. Because of the complexities, control procedures may be only partially effective.

Bumblefoot.

Large swellings or hard cores developing in the foot or foot pad are believed usually to be the result of repeated bruising or injury to the foot and/or bacterial invasion of the foot through bruised areas or via penetrating wires, splinters, or other sharp wires or objects.

The likelihood of bumble-foot is increased by insufficient deep, cushioning litter; sharp edged roosting boards; caked litter or other damp unsanitary walking surfaces; and allowing heavier birds to rest on and jump from excessively high perches.

A lack of vitamin A or other vitamins may heighten the chances of some birds developing bumblefoot.

Cannibalism.

As used here, cannibalism refers to harmful picking and clawing activities performed by certain members of a bird or poultry flock against others. Weaker or smaller stock usually are the victims of cannibalism.

Overcrowding and high temperatures have been associated with the increased occurrence of cannibalism, along with a lack of enough fiber in the ration. An insufficient number of feeders seems to increase cannibalism.

Boredom a Factor

Lack of exercise, and boredom from being able to consume all daily feed requirements too quickly, also are suspected in relation to cannibalism.

This problem sometimes has been overcome by providing poultry and other birds with treats of greens, chunks of leafy hay, whey blocks, rolled newspaper, or other items with which they may exercise and satisfy some of their natural clawing and pecking instincts.

Providing less feed but at more frequent intervals may also help to avoid cannibalism both in poultry and in cage pet birds.

When cannibalism becomes a problem, ordinarily you should begin your first efforts at correcting overcrowding. In some instances, this may require moving a portion of the flock to other quarters; separating larger, faster growing birds from smaller, possibly less aggressive but still valuable, slower-growing birds; or identifying and re-moving the main troublemakers. Beaks and face feathers of the most cannibalistic birds may be obviously bloodstained, helping in identification.

Debeaking (removing part of the beak) is practiced widely to control cannibalism in commercial poultry. Metal or plastic clip-on eyeshields or "specs" also have been used to make it difficult for birds to peck accurately. Decreasing the temperature and brightness of pens may be a further help in reducing cannibalism.

In many instances feather picking is an early form of cannibalism. The same causative factors apply. Feeding changes, reduction of boredom, control of external parasites, and reduced lighting may prevent poultry, game birds and pet cage birds from developing feather picking into the worse habit of cannibalism.

Egg Problems

Unlaid eggs sometimes accumulate in the oviduct, the tubular organ where the egg-white and shell are formed. The abdomen of affected birds can become severely distended from this condition, called egg binding. The problem is discussed further in the chapter on pet bird diseases.

A similar disorder that also can cause abdominal enlargement results when egg yolks released from the ovary fail to pass into the oviduct, thus accumulating in the abdominal cavity. The causes of these problems are ill-defined, but may be related in part to conditions that produce obesity, flightiness or nervousness.

Other reproductive ailments perplex flock owners and scientists. Some of these disorders such as salpingitis (distension of the oviduct with whitish curdy material or yellow cheesy cores) may be due to viral, bacterial, or mycoplasmal infections prior to maturity.

Abnormal soft or misshapen eggs, ruptured egg yolks, and prolapse or "blowout" of the oviduct frequently are associated with management and feeding problems. Infections with such respiratory viruses as Newcastle or bronchitis virus frequently result in weak or misshapen eggshells or watery whites.

Lameness.

Leg weakness in birds or poultry has such a vast number of potential causes that their adequate discussion is beyond the scope of this chapter. A combination of inherited, nutritional, and infectious factors may be involved.

The most useful tips for keepers of small flocks and aviaries are: 1) Keep hatchlings and young growing birds off slippery surfaces and, 2) Provide these young birds, and their breeder parents, with the most nutritionally complete ration possible.

A common cause of one-legged lameness in pet birds, especially parakeets, is kidney tumors.

Deformities.

Malformations often draw considerable attention, but they generally unless very extensive in a flock or aviary are only of passing interest.

One disorder, sometimes called "wind puffs," causes a bird's body to rapidly become unusually large and rounded. When examined, affected birds are found to be very puffy and light.

Wind puffs usually are due to accumulations of air under the skin after a tear or rupture occurs in one of a bird's natural internal air sacs following a flying injury, castration surgery done to produce fatter heavier males (capons), or possibly the heavy breathing and coughing that may accompany severe respiratory infection. Valuable birds can be treated surgically.

Edward T. Mallinson is Associate Professor, Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland campus, College Park.