Egg binding is a medical condition where a hen is unable to lay an egg that has formed inside her body. This problem is a medical emergency, with fatal consequences if the egg binding is not relieved.

Causes. There are many possible causes of egg binding, but it's believed that the most common one is calcium deficiency. Adequate calcium is essential to the formation of normal, hard-shelled eggs, and also to normal muscle function in the hen while she is trying to push the egg out of her body. Insufficient calcium can result in the production of soft-shelled and no-shelled eggs, which can be difficult to pass because the hen's body can't get a proper grip on them.  Internal breakage or leaking of the egg's contents can cause dangerous medical problems for the hen including impacted soft-shelled eggs and egg yolk peritonitis.   See the Cockatiel Breeding Diet article for more information on calcium and the vitamin D3 that is essential for calcium absorption.

Vitamin A deficiency is also a serious problem. According to Comparative Avian Nutrition (Klasing), it is the most likely vitamin to be deficient in either wild or captive birds. Without enough vitamin A, the mucous lining in the oviduct will become dry and hard. It is difficult or impossible to pass the egg without this lubricant. Vitamin A itself is not present in most foods, but many plant foods are rich in beta carotene which is converted to vitamin A in the body.  So make sure the diet includes plenty of leafy greens and orange vegetables like carrots to provide beta carotene. Nutritionally complete pellets and Nutriberries are also a good source of vitamin A.

Another common cause of egg binding is lack of muscle strength in the hen due to illness or lack of exercise.  It's important for hens to be well-nourished, healthy, and physically fit before they breed.  Flying is an excellent exercise that improves muscle tone throughout the body.

Hens that are not in excellent condition should be prevented from laying eggs if possible; see the Hormone Control article for more information. Single (unmated) hens in particular should be discouraged from laying eggs since the eggs will obviously be infertile. Every molecule of physical material in an egg has to come from the hen's body, and laying infertile eggs is an unnecessary strain on her physical resources.

Hens that are very young (less than 18-24 months) or very old are at higher risk for egg binding than a hen that is of prime breeding age.

A breeding hen will typically lay eggs at the rate of approximately one every 48 hours, and the average clutch size for cockatiels is 4 to 6 eggs. A hen that has been acting nesty, or who doesn't produce an egg "on schedule" should be watched carefully for signs of egg binding.

Symptoms of egg binding may include distended abdomen, weakness/lethargy, difficulty in standing or walking (including wide stance or possible leg paralysis cause by nerve compression), tail wagging or bobbing, labored breathing, straining to pass the egg, and/or inability to pass feces. An eggbound hen will often huddle on the cage floor with fluffed feathers. In extreme cases there may be a prolapse of the oviduct, meaning that tissue that is normally inside the body is hanging outside the body through the vent; the egg may or may not be hanging outside the body too.  Not every hen will show every symptom, so possible egg binding should always be considered when just some of these symptoms are present.

Treatment. Egg binding is a true medical emergency so if possible, contact your avian veterinarian ASAP. A vet has access to diagnostic tools (like X-ray) and medical techniques (like calcium injections or surgical removal of the egg) that may be essential for saving your hen's life. The sooner the egg binding is relieved, the greater her chances for a full recovery will be.

If you don't have access to skilled veterinary care, there are home remedies that sometimes work.  

1. Liquid calcium: a drop of liquid calcium with vitamin D3 placed directly in the beak can relieve egg binding almost immediately in cases where the hen's muscle function was impaired by calcium deficiency. It will not strengthen the eggshell of an existing soft-shelled egg.  Liquid calcium made for birds is preferable, but a liquid calcium product for humans can be used if necessary. If a human product is used, look for one that does NOT contain zinc or iron.

2. Warmth and humidity can be helpful. One common technique is to put the hen's cage in the bathroom and run hot water in the shower until the room is steamy.  You can also stand the hen in a bowl of warm (not hot) water. Some sources recommend carefully holding the hen above a bowl of steaming water, but this seems dangerous due to the risk of steam burns. You can place a heating pad under half the cage, leaving the other half unheated to give your hen a choice of temperatures.  But if she is having mobility problems you will need to watch her carefully to make sure she doesn't get overheated.

3. Lubricating the vent with KY jelly or some kind of oil (baby oil, mineral oil, cooking oil) may be helpful.

4. Providing an electrolyte boost or some fast energy from sugar might be helpful. Have the hen drink a small amount of Pedialyte or Gatorade for electrolytes, or eat a bit of honey, Karo syrup or sugar water for a sugar rush.  There is a simple recipe for homemade Pedialyte here. You can use an eyedropper or plastic syringe to put drops of fluid directly into her beak.

DO NOT attempt to massage or pull the egg out of the hen's body yourself, and do not handle her in a way that could make the egg break inside her.  You will do more harm than good, with fatal results.

In case of a prolapse, it is necessary to keep the exposed tissue moist to keep it from dying; you can rinse the tissue with warm running water.  If the egg is protruding from the body, you MUST get veterinary help to save the hen's life; do not try to solve this problem yourself. If the egg is NOT protruding from the body, you may be able to push the tissue back into the body. One technique is to rinse the area and blot it semi-dry. Then coat the entire exposed membrane with sugar and let the sugar sit on the tissue for 10-15 minutes. Rinse off the sugar and use a damp Q-tip to gently push the tissue back in the body. Another alternative is to put KY jelly on the exposed tissue and push it back into the body, and a variety of other methods are recommended on the internet. The prolapsed tissue may stay inside the first time you push it into the body, or it may take two tries to keep it in. if the tissue won't stay in, keep it moist and get to a vet ASAP