Avian Obesity
By Tom Roudybush

Obesity is a common finding in pet birds. If your bird's body weight exceeds the normal or expected body weight for that species by 15 percent or more, it is likely to be obese. This condition is hazardous to your bird's health because of increased risks of heart disease (in the longer-lived parrots), fatty tumor formation, egg binding and respiratory distress during excitement or exercise. If your bird needs to be anesthetized for any reason, it will have increased risks of complications. In addition to these health risks, breeding success can be decreased in obese birds because of infertility.

Table 1. Approximate Normal Body Weights (grams) Species Average Weight + or - Scarlet Macaw 1001 151 Blue and Gold Macaw 1039 102 Military Macaw 925 57 Hyacinth Macaw 1355 95 Umbrella Cockatoo 403 57 Moluccan Cockatoo 577 71 Greater Sulfur Crested Cockatoo 843 147 Citron Cockatoo 357 34 Grand Eclectus Parrot 432 40 African Grey Parrot 554 66 Blue-fronted Amazon 432 51 Mexican Red-headed Amazon 360 24 Yellow-naped Amazon 596 85 Double Yellow-headed Amazon 568 61 Budgerigar 30 Lovebird 45 Cockatiel 80 Taken from Clinical Avian Medicine and Surgery, Harrison and Harrison, 1986, Appendix 4, p.662.

Clinical Signs of Obesity

Table 1 shows some normal weight ranges for some species of birds. Comparing the body weight of your bird to these reference ranges is one method of diagnosis. Some very large-framed individuals may be 15 percent heavier than these figures and not be obese, but these would be the exception. Obesity may be seen as bald patches in certain areas where the feather tracts have separated because of large deposits of fat under the skin. Your bird may have a wide stance, with legs spread further apart than a normal bird. There may be a roll of fat, a "double chin" visible under the beak.

When a bird is handled, yellow or white fat deposits are most likely to be found in the abdomen, seen as a distended, doughy abdomen, and under the skin along the flanks and inner thighs, and around the crop and upper breast area. Moistening the feathers and skin with alcohol in these areas will help you to see the fat.

Causes

Obesity is caused by a larger calorie intake than calorie use over a period of time. This situation is most likely to occur in pet birds with limited exercise and high calorie and high fat diets. Birds that are fed diets with large proportions of sunflower seeds, peanuts and walnuts are often prone to obesity. If you feed your bird high fat or high calorie human foods, such as cheeses, meat, whole milk, cookies and cake, you can create obesity. Boredom may also predispose a bird to obesity. The bird may just sit at the food dish all day, eating.

Treatment

The most effective way to treat obesity is to increase exercise and decrease calorie intake at the same time. Place the food and water at opposite ends of the cage, especially with one high and one low, forcing the bird to move about the cage more. Make sure your bird finds the new locations for the food and water and is still eating and drinking. Cage or flight size can be increased or time outside the cage to exercise may be increased. If boredom is a problem, adding toys to the cage or increasing attention to the bird may be a solution.

Feed restriction will probably not be the most satisfactory method, because it does not satisfy your bird's hunger and a vitamin or mineral deficiency could occur. Changing the diet to a temporary reducing diet followed by a permanent low-fat diet is probably the most efficient and most satisfactory way to treat obesity.

Significant weight loss, such as occurs when treating obesity, should be done under guidance from your veterinarian. Your bird must be closely monitored to assess the rate of weight loss and to assess whether any newly substituted diet is being eaten. Higher-fat foods taste better than low-fat foods; so a bird used to fatty foods may be quite reluctant to eat low-fat substitutes. You should clean the bottom of the cage daily, using paper as cage liner so that the size and color of the droppings can be checked daily. If your bird is not eating, the droppings will appear small and dark green or black. As your bird begins eating more the fecal portion of the droppings will get lighter green and will be larger and more fleshed out. Become familiar with what your bird's normal droppings look like before the switch. Weight loss should not exceed 3 percent per week. If your are unable to weigh your bird weekly at home, weekly weigh-in appointments should be scheduled with your veterinarian.

Birds should be housed individually when making diet changes. If more than one bird is being treated for obesity, they should still be housed separately during the transition to a new diet so that you can monitor the droppings of each bird. If you must house more than one bird together, you should weigh the birds more frequently, twice weekly, to keep track of what each individual is doing. In the case of one obese bird and a normal mate, it is best to separate them during the weight reduction process so only the obese bird is feed restricted or given a reducing diet.

If lipomas are present they may disappear with the weight reduction. If they are still present after a normal weight is achieved, your veterinarian should pursue medical management or surgical removal.

Dietary Management

To achieve weight reduction, a temporary reducing diet may be indicated. The best diet for weight reduction is a low energy, low fat, high fiber diet, such as Roudybush Formula AO. Birds used to consuming a large quantity of a high-energy food will be unable to consume the same number of calories with such a diet offered free choice. Formula AO has the same levels of protein, vitamins and minerals as the maintenance diet, but the metabolizable energy is about 2650 kcal/kg compared to 3250 kcal/kg in the maintenance pellet. Formula AO is formulated to be the sole source of food for the bird, but small amounts of fresh fruits and vegetables can be given as treats.

If your bird is already eating pellets or crumbles as part of its diet, switching to the Formula AO pellets or crumbles should be a simple process. Remove the old diet and replace it with Formula AO. Clean the cage at the time of the switch so you can observe the droppings to make sure your bird is eating. If the bird is on an all-seed diet, it may not recognize the pellets or crumbles as food. There are two methods of switching such a bird onto the diet. One method is to remove the old food and offer nothing but pellets or crumbles. This should only be done with a bird that can be closely monitored by weighing twice weekly and observing droppings on a daily basis. If more than a five percent body weight is lost in the first week, the bird should be put back on the old diet for one week before repeating the process. The second method is to gradually introduce the pellets or crumbles mixed in with the old diet. Start with one-quarter Formula AO mixed with three-quarters original diet. After one week, increase the proportion of Formula AO to one-third. During the transition, you should weigh your bird weekly. If your bird is losing more than five percent of its body weight in any one week, go back to a proportion of Formula AO that it will lose 3 percent or less on for a week before continuing with the diet change. Make gradual increases in the proportion of Formula AO on a weekly basis until the diet is 100 percent Formula AO. At that time, you should observe your bird's droppings daily to make sure it is eating the Formula AO. This is a safer method, especially if your are unable to closely monitor your bird.

Once the weight reduction has been achieved, switching the bird onto a maintenance pellet or crumble can be accomplished by simply substitution the reducing diet with the maintenance diet. Typical seed mixtures have about 17 percent fat as opposed to 3 percent fat in Roudybush Daily Diet. Putting your bird back on seeds will increase its chances of becoming obese again. After the bird is put onto a maintenance diet, it should be weighed every two to three weeks for two to three months to be sure that it is not regaining excessive weight. If the body weight is staying relatively constant, yearly checkups and weigh-ins should be sufficient follow up.

Roudybush Formula AO is sold only through veterinarians. Use this diet only as directed by your veterinarian. Feeding this diet to growing birds may result in nutritional disease or death.

Obesity can be prevented, treated and managed by proper feeding and exercise. Your birds have a much better chance to live longer, healthier lives when they are offered proper nutrition and are kept lean.

Tom Roudybush has researched ways to promote growth and longer life in birds for more than 30 years. He has published nutritional information on parrots and other hookbills.