What is egg binding?
Egg binding occurs when a female bird is unable to naturally expel an egg from her body, a condition commonly referred to as “egg bound”. While most female birds have no problems laying eggs, occasionally they may encounter difficulty. When detected early, egg binding may be resolved easily. If a prolonged period has elapsed since a bird began attempting to lay an egg, she may become critically ill.
"Many bird owners are surprised that a female bird will still lay eggs even when not exposed to a male."
Many bird owners are surprised that a female bird will still lay eggs even when not exposed to a male. Remember, human females ovulate regardless of the presence of a male, so it makes sense that a female bird can ovulate without a male present. The major difference is that the egg or follicle is microscopic in people, whereas in birds, the follicle becomes large, has a shell formed around it, and is expelled from the bird. Not all female birds will lay, but they are all capable of laying eggs.
What causes egg binding?
There are numerous reasons for egg binding. Many birds are fed a nutritionally unbalanced diet. Seed-based diets are deficient in many vitamins and minerals, especially calcium, selenium, and vitamins D and E. Consumption of a nutritionally deficient diet may cause poor follicle quality, poor egg shell quality, and/or low levels of calcium that prevent the oviduct from contracting to push the egg out of the reproductive tract and out of the body.
Soft-shelled or shell-less eggs and other egg malformations resulting from improper levels of dietary calcium may also lead to problems. Obesity (from lack of exercise or a high-fat, all-seed diet), hereditary factors, old age, and improper laying environment are all other potential causes of egg binding. Traumatic injuries and diseases affecting the vent (the opening where feces, urine, and eggs pass out the body) may also affect the hen’s ability to lay an egg.
Are certain birds prone to develop egg binding?
Yes. Small birds, including budgerigars (parakeets), canaries, cockatiels, finches, and lovebirds often have problems related to egg laying, although any female bird can become egg bound.
How can I tell if my bird is egg bound?
Many owners do not even know their bird’s gender and often do not suspect egg binding as a cause of their bird's illness. A thorough examination by an avian veterinarian will help determine to root of your bird’s illness. In many cases, an X-ray shows a calcified egg in the abdomen if egg binding is the cause of the illness.
A healthy female bird that is in the process of laying eggs should pass a formed egg within 24-48 hours of its formation as a follicle on the ovary. How many eggs a bird lays successively depends on the species, age, and health of the bird. Birds that are egg-bound display the following symptoms:
- may or may not have passed an egg within the last 48 hours;
- are usually weak, not perching, often sitting low on the perch or on the bottom of the cage;
- are usually straining as if trying to defecate or lay an egg;
- usually have a noticeable swelling of the abdomen;
- sometimes have an egg bulging out of the vent, or it may be retained in the oviduct or cloaca (the common chamber that collects the reproductive, urinary, and gastrointestinal tracts), which then prolapses or has tissue pushed out of the vent; and
- may not be able to stand or may have trouble grasping the perch if the egg puts pressure on the nerves that control the legs.
Since the signs associated with egg binding are also seen in sick birds with other causes of illness, diagnostic testing is essential in formulating a proper diagnosis.
How is egg binding diagnosed?
During the physical examination, your veterinarian may feel a firm, egg-shaped mass inside your bird’s abdomen. Usually, X-rays (radiographs) are needed to confirm the presence of the egg inside, especially if the egg has a shell around it. Some eggs get stuck before the shell is formed. These shell-less eggs are harder to confirm on X-ray and sometimes require a sonogram (ultrasound exam) to detect their presence. In some cases, there may be more than one egg stuck in the patient’s oviduct.
Early diagnosis of egg binding is important, as small birds can die within a few hours of becoming egg-bound, due to compromised circulation and pressure on their airways from the trapped egg.
How is egg binding treated?
Treatment varies depending on how sick the bird is, where the egg is located, and how long the bird has been egg bound. Critically ill birds are first treated for shock, and then attempts are made to extract the egg. Mildly affected birds may respond to supplemental heat, rehydration with injectable fluids, calcium, vitamin D3, and oxytocin, a hormone that causes the oviduct to contract and help expel the egg.
If the egg is near the cloacal opening, your veterinarian may be able to sedate your bird and then gently extract the egg with cotton swabs, a medical lubricant, and gentle massage. Eggs that do not pass with these therapies require more aggressive therapy. Your veterinarian may need to pass a needle through the vent and into the eggshell to draw out the contents of the egg (aspirate), causing the shell to collapse. Following this treatment, your veterinarian may pull out the empty shell or leave it to pass out of the bird within a few days.
If your veterinarian cannot see the egg through the vent, surgery under general anesthetic may be necessary to remove the egg. In advanced cases where there is disease, cancer, or infection involving the oviduct, a salpingohysterectomy may be recommended. This procedure involves removal of the entire oviduct while leaving the ovary intact.
Can egg binding be prevented?
Birds on a poor diet, such as sunflower seeds and nuts, should have their diet changed to a nutritionally complete, pelleted diet, according to specific instructions from your veterinarian. They may recommend calcium, phosphorus, and vitamin and mineral supplementation.
Obese birds should be encouraged to lose weight through diet change and increased exercise. Birds that are chronic egg layers are commonly treated with hormonal drug therapy to stop egg laying temporarily so that their bodies can recover. A salpingohysterectomy (removal of the entire oviduct) is typically the last-choice therapy when medical and egg extraction through the vent are not possible. This surgery is moderately risky and should only be performed by an experienced avian veterinarian. Birds that are weak and/or thin have a higher risk of not surviving the surgery.
If you have a female bird that is showing hormonal tendencies such as tearing up paper in the cage, constantly looking for a place to hide, or lifting their tail to rub their vent on objects in the cage, you will need to take one or more of the following actions:
- Limit light hours to 8 hours a day
- Stop stroking or petting the bird for a month
- Limit high-energy foods like fruits and nuts for several weeks
