Nutritional Disorders of Pet Birds

Obesity is common in pet birds and is caused by high‑fat diets (seeds, nuts, and many table foods), too much food, and lack of exercise. A bird is considered obese if it weighs 20% more than its ideal body weight.

Galah cockatoos, macaws, Amazon parrots, and Quaker parrots are especially likely to become obese. Symptoms of obesity can be hard to notice. Some obese birds become lame or have breathing difficulties because of their excessive weight. In birds, just as in people, obesity increases the risk of arthritis, fatty liver disease, atherosclerosis (fat deposits in the arteries), and heart disease.

To encourage an obese pet bird to lose weight, you should feed it a measured amount of a nutritionally balanced pelleted diet. Your veterinarian can advise you about how much to feed your bird.

Obese birds should also be encouraged to exercise. One way you can do this is to provide your bird a larger cage with several food bowls placed apart to promote movement. Rope or spiral perches encourage climbing and balance. Birds that can fly should have access to a safe outdoor flight cage. Birds that can't fly should be encouraged to walk or climb stairs.

Vitamin A deficiency is common but often overlooked in pet birds. Birds with diets that consist largely of seeds and nuts are at highest risk because these diets are low in vitamin A and many other nutrients, and too high in fat. But giving your bird large amounts of vitamin A supplements can be dangerous and might cause reproductive problems, bone deformities, and liver disease.

The best way to prevent vitamin A deficiency in your pet bird is to feed it a nutritionally complete and balanced pelleted diet containing safe levels of provitamin A compounds such as beta‑carotene, which can be converted to active vitamin A in the bird’s body and are less likely to be toxic than are high doses of vitamin A itself.

Besides feeding your bird pelleted food, you can offer smaller amounts of fruits and vegetables that are rich in vitamin A, such as cantaloupe, papaya, chili peppers, broccoli leaves and florets, sweet potatoes, turnip greens, collards, endive, butter, liver, egg yolks, beets, dandelion greens, and spinach.

The symptoms of vitamin A deficiency that a bird might show depend on which body system (reproductive, digestive, or respiratory) is affected. Common symptoms include discharge from the nose, sneezing, swelling around the eyes or sinuses, difficulty breathing, increased drinking and urinating, poor feather quality, feather plucking, sore feet, and loss of appetite.

White, sticky areas of discharge might develop in the bird's mouth, eyes, and sinuses. These can become infected and form large abscesses (pockets of pus) that block the opening of the trachea (main airway for breathing), causing labored breathing and possible suffocation. Abscesses can also block the choana (the opening in the roof of the mouth that leads to the sinuses), causing heavy discharge from the nose and swelling of the eyes. Birds with any of these signs should be seen by a veterinarian.

In birds, the thyroid gland is located inside the chest rather than under the skin in the neck, where it is in people. When birds are fed an all‑seed, iodine‑deficient diet, the thyroid enlarges and presses on the trachea (main breathing airway) and esophagus, causing a condition called goiter.

Typical symptoms of iodine deficiency in birds include loud or harsh breathing, wheezing, clicking sounds, and changes in voice. In severe cases, the bird might regurgitate food.

A common treatment for iodine deficiency in birds is to add an iodine supplement called Lugol's iodine to the bird’s water until the bird can be transitioned to a nutritionally complete pelleted diet.

Seed‑based diets are low in calcium and vitamin D and high in phosphorus. Many parrots prefer sunflower seeds, which are low in calcium and protein and high in fat.

Calcium, phosphorus, and vitamin D work together in the body, and an excess or deficiency of one in the diet affects the balance of the others. In birds, a balanced diet that doesn't have too many seeds and nuts helps prevent these imbalances.

Vitamin D in the diet is converted in the body to an active form when the bird’s skin is exposed to sunlight. Active vitamin D is needed for proper calcium uptake from food.

Birds that are fed diets low in calcium and/or vitamin D, especially if they are housed indoors away from sunlight, can develop metabolic bone disease. In this condition, bones become soft, deformed, and easily fractured. Affected birds must be transitioned to a more nutritious pelleted diet and be given vitamin D and calcium supplements.

Seeds don't contain much calcium. Acute (rapid-onset) hypocalcemia (a low level of calcium in the blood) is a condition of birds that is more common in birds (especially African grey parrots) that are fed all‑seed diets.

Symptoms of acute hypocalcemia in birds include weakness, tremors, and seizures. The exact cause is unknown, but abnormal functioning of the body's parathyroid gland, which is involved in processing calcium, is suspected.

Calcium that is injected or given by mouth can lead to rapid improvement in birds with acute hypocalcemia. Ongoing treatment includes calcium supplements and exposure to several hours of direct sunlight or artificial ultraviolet (UV) light each day, which is needed for the body to make the vitamin D that is required to absorb calcium from the diet. Special UV bulbs designed for birds (not plant or reptile bulbs) should be used.

Although high calcium intake is usually not a problem in birds, too much vitamin D in the diet can cause calcium to be deposited in organs such as the kidneys. Vitamin D supplements must be given with care, and excess vitamin D should not be given to certain species, such as macaws, that are especially sensitive to high levels of vitamin D.

Iron storage disease occurs in birds when excessive iron builds up in the liver. Iron is needed to produce hemoglobin, which carries oxygen in the blood. When too much iron is present in the diet, it is stored in the liver, heart, lungs, and other organs, causing severe damage and often death, sometimes without warning signs.

Symptoms of iron storage disease in birds can include weight loss, low energy, swollen abdomen due to fluid buildup, breathing difficulty, and circulatory failure. A liver biopsy is required to diagnose the condition.

Iron storage disease in birds can be treated by removing excess iron from the body by taking blood repeatedly at intervals, administering medications that bind iron in the blood, and giving foods that contain less iron.

Iron storage disease is common in pet mynahs, toucans, and some zoo birds, such as birds of paradise. It has also been reported in parrots, particularly lories.

Although excess dietary iron is a major factor in this disease, not all birds on similar diets are affected. Stress and genetics can also be involved. Foods rich in vitamin C, such as citrus fruits, increase iron uptake. Too much vitamin A in the diet can also play a role.

Bird species prone to iron storage disease—like mynahs, lories, lorikeets, and toucans—should be fed diets low in iron (with less than 100 parts per million [ppm] of dietary iron) and should not be given citrus fruits.

Fruits that have low amounts of iron include peaches, plums, honeydew melon, and peeled apples. Bananas, mangoes, papaya, summer squash, and peeled boiled potatoes have slightly higher but acceptable iron levels.

Foods to avoid feeding your bird include iron‑fortified baby foods and juices, table foods enriched with iron or ferrous sulfate, animal products, primate biscuits, and large amounts of citrus fruits.

• Also see professional content regarding nutritional diseases of pet birds.