Egg binding refers to a medical condition in birds or other egg-laying animals, where the female is unable to pass an egg that has formed. The egg may be stuck near the cloaca or further inside. Egg binding is reasonably common and potentially a very serious condition that can lead to infection or damage to internal tissue.
The bound egg may be gently massaged out by a certified vet practitioner but it may become necessary to break the egg in situ and remove it in parts. An untrained person should never try to remove an egg by massage because if the egg is broken in the process, the oviduct must be cleaned of shell fragments and egg residue to avoid damage or infection.
Most wild birds have a specific breeding season but captive birds can reproduce at any time because the environmental clues that signal it's time for breeding, photoperiod, nutritional status, presence of a mate (bird or human), and/or the presence of a nest site are present most of the time in manner in the home. Light and heat and lots of good food and loving owners all can stimulate a female into a reproduction cycle. A normal, healthy hen will likely lay at some point, the issue comes if she cannot pass an egg or is a chronic layer.
Females store calcium in their bones (hyperostosis) that is later used in egg shell production. Ovulation occurs in response to increasing levels of estrogen and luteinizing hormones. The oviduct is composed of four segments: the infundibulum, where fertilization occurs; the magnum, where albumen is deposited; the isthmus, where the inner and outer shell membrane is added; and the uterus (shell gland), where calcification of the shell occurs. The entire period of egg formation takes approximately 24 hours. Most pet birds lay 2 to 4 eggs in a clutch, although indeterminate layers such as cockatiels and budgerigars can produce much larger clutches.
Dystocia (egg binding) is a common occurrence in captive hens. Usually, these birds are chronic egg layers and calcium deficiency is a factor (resulting in misshapen or soft-shelled eggs). Removing eggs from a nest (a common practice by breeders) will make a hen produce a new egg to replace the missing one, which results in further calcium depletion and increases the likelihood of egg binding. This is why you should never take an egg from a hen ... if she lays it let her sit on it until it either hatches or she tires of it.
Other causes of egg binding can include vitamin A deficiency, oviductal disease or neoplasia, abdominal wall herniation, being a first-time layer, and other genetic factors. Obesity, general nutritional inadequacy, behavioral factors, and husbandry conditions may be involved. In an article about Reproductive Diseases of Pet Birds, Dr. Sharman M. Hoppes, DVM, ABVP (Avian) of Texas A&M University discusses egg binding. Dr. Hoppes points out that egg-bound birds usually present as emergencies. These birds should first receive supportive care (i.e., rehydration, parenteral calcium, increased humidity, and warmth) before attempting extraction of the egg.
Clinical signs of an egg bound bird include a bird sitting on the bottom of the cage, depression, closed eyes, bobbing tail, dyspnea (labored breathing) and the abdomen may be distended. An egg is not always palpable and diagnostic tests may need to wait until the bird is stable, but the tests include a CBC, plasma biochemical profile (including ionized and total calcium), and radiographs. These tests may need to be done in stages for a critical patient.
If the egg is adherent to the uterine wall or unable to be passed (often due to swelling, adhesions, or collection of feces and urates), administration of drugs that cause uterine contractions and induce oviposition could theoretically lead to uterine rupture. If medical management fails, then sedation and manual extraction may be required.
Surgical intervention (salpingohysterectomy) is warranted if the egg is severely adhered to the oviduct, multiple eggs are present, or the egg is ectopic. Prognosis for egg binding is fair to good if medical treatment or manual extraction of the egg is effective. In the case of chronic layers husbandry, nutritional, and behavioral issues need to be addressed.
From an article written by Dr. Amy Crouch, BVSc (Hons) BSc (Hons), Brisbane Bird Vet, a bird was brought in for veterinary examination. The bird was very overweight, weak, depressed and had fluffed feathers. There were feces stuck to her vent (external constipation). The feather quality was poor. There was abdominal distension, and an egg‐like structure could be palpated within her abdomen. She was in respiratory distress and exhibited a distinct tail bob.
Blood tests were performed which showed that she had severe inflammation and some minor liver problems. The inflammation was due to the egg binding and the liver problems were likely to be dietary based (a seed diet causes liver disease in birds). Lulu was hospitalised. Calcium was administered by injection into the pectoral muscle. This was given as it is required for the oviduct to contract and expel the egg.
Leuprolide (lucrin) therapy was initiated; this medication reduces oestrogen levels in the bird and therefore reduces reproductive activity and allows time for healing of the reproductive tract and prevents further cyclic activity. Pain relief was also provided to make Lulu more comfortable. Nutritional support was given by force‐feeding and she was also placed in a heated room. Lulu had still not passed the egg the following day. Therefore she was given a short general anaesthetic and the intact egg was imploded (collapsed). Read the full article here.
From the Avian Examiner, March 2013, if an egg-bound hen requires veterinary intervention, the first step, of course, is to attempt to manipulate the egg down the oviduct and deliver it from the cloaca via gentle palpation. If this fails, the egg must be removed mechanically. The primary key to removing a static egg from the oviduct is to wait until the egg is actually visualized at the vaginal opening before it is broken and extracted. Collapsing the egg too soon when it is positioned higher in the oviduct may result in incomplete removal of shell and lead to further complications.
Failure to intervene when a hen is egg bound can result in cloacal prolapse. Cloacal prolapse can occur in any bird that strains frequently as is seen in egg-bound hens. If detected and treated early, surgery combined with behavioral modification may correct the problem and prevent secondary infections and other complications. If the egg ruptures, then egg yolk coelomitis will result. The yolk, along with bacteria (eg, Escherichia coli, Staphylococcus) in the coelomic cavity results in infection. Egg yolk coelomitis causes a severe inflammatory reaction and can lead to an egg-related pancreatitis or a yolk emboli (which can resemble a stroke).
Egg binding is a serious medical issue for your bird. She may be able to pass the egg with supportive care described above but if she is a first-time layer or is showing any of the symptoms of egg binding (described above) then make sure you get her to an Certified Avian Vet for medical intervention.
Original publication January 2, 2017, reprinted and edited from the author's original work.