Here are some basic guidelines if she's having trouble passing eggs:
Low Calcium Levels: If a hen is low or lacking in calcium she will not be able to put on a hard shell. The shell needs to be nice and hard so when the muscles contract, the egg is easier moved through the oviduct. If it is soft, these types of eggs are not able to move as easy. Calcium also plays a role in the contractions of the entire vviduct and shell Gland. So, if she is low on calcium, the muscles will not contract well enough to expel the egg. Suppliment with Calciboost or Calcivet or similar product available in your local feed store.
Malnutrition or a bad diet: A hen that is deficient in many nutrients and vitamins can become egg bound very easily. Vitamin D3, magnesium and phosphorus need to be in the right proportions for the hen to break down and make the calcium usable inside her body. If she is not eating right, this will contribute to the lack of calcium in the shell or the contractions to expel the egg. Make sure that a high quality layer food is being offered.
Dehydration: Water is very important for the process of pushing the egg out. If she is dehydrated the oviduct can become dry, hence the egg is not going to move out properly. Make sure water is always available and in more than one location...particularly in the summertime heat.
Being sedentary or fat: Hens that do not get enough exercise, have not developed or lost good muscle tone or have too much fat in their abdomen will have trouble passing eggs properly. Buy her a treadmill. Just kidding.
Large or misshapen eggs: If the hen is producing unusually large eggs or oddly shaped eggs, these types can become stuck easily if they are unable to pass through the pelvis. Many times overly large eggs are genetic in origin. Misshapen eggs can be caused from something having gone wrong in the reproductive system, eggs backing in on each other, or a defective shell gland. Of course, if the hen just can't seem to put a shell on the egg, the shell gland could be deemed defective.
Illness: Any illness that causes weakness, lack of appetite, low consumption of water or other reactions to being ill can cause the hen to be unable to pass an egg. She would need a thorough exam and testing by an avian vet (please see here: www.aav.org) which may not be reasonable financially in your operation.
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