Egg binding occurs when a hen attempts to expel an egg but is unable to do so. Egg binding shoulfd be considered a serious emergency. It can result in shock, circulatory collapse and death, if left untreated.
Egg bound hens usually appear distressed. They may be weak, depressed, puffed, exhibit rapid breathing and sit on the bottom of their cage.
Repeated unproductive straining may be observed and droppings may or may not be passed. Lameness may be noticed as a result of the egg’s pressing against the ischiatic nerve which innervates the leg.
Diagnosis may be made upon physical examination and history of the hen’s having laid eggs in the past. The egg may be palpable in the abdomen if it is low. A radiograph is often taken to confirm the presence of the egg, it’s position and to evaluate its size, shape and the presence of an additional egg. If the shell is not calcified, it will be difficult to see radiographically. Ultra-sound may be very helpful in this case.
It is important to remember that during the normal egg laying process, an egg remains in the shell gland for 18 hours. Thus every hen with a palpable egg is not necessarily eggbound.
If the bird is stable, conservative medical treatment is usually attempted and often successful. The bird is placed in a warm environment. Fluids, dextrose and injections of calcium, vitamins and hormaones may be administered. The vent is often lubricated with sterile KY jelly and the bird is allowed to attempt passage of her egg by herself. If she is not eating, she may be tube fed.
If the hen is distressed or if the egg does not pass within 24 hours, the hen is anesthitised with Isofluran or Sevoflurane and an attempt is made to manually deliver the egg by gentle downward pressure on the abdomen. Great care is taken to avoid breaking the egg inside the bird.
If the egg is too large or is unable to be manually delivered, ovocentesis may be performed. This consisits of inserting a large bore needle into the egg and aspirating the contents into a syringe. This is necessary because release of the egg’s contents into the abdomen may cause a severe inflammation known as peritonitis.
If the egg can be visualized through the cloacal opening, a needle may be inserted into the portion of the egg visualized, the contents aspirated into a syringe, and the shell gently crushed. The shell fragments may be removed through the cloaca.
If the egg is too large and can’t be visualized through the cloaca, ovocentesis may be performed transabdominally and the contents aspirated. The shell may then be crushed gently. The hen often passes the shell fragments over several days. If she does not, surgery will be necessary.
Part II will address the causes of egg binding and what may be done to stop egg laying.