Written by: Dr. Jacquie Jacob, University of Kentucky

Cage layer fatigue is the equivalent of osteoporosis in chickens. It is a condition that primarily affects caged chickens that are at a high level of egg production (hence the name), and its cause is believed to be at least partially nutritional. Many layers are able to recover quickly from cage layer fatigue when they are removed from the cages and allowed to walk normally on the floor. Because exercise seems to alleviate the condition, lack of exercise in caged hens may be a partial cause.

Young layers at peak production require a large amount of calcium. If there is not sufficient calcium in the feed, the hen makes use of calcium stored in a special type of bone (referred to as medullary bone). As more and more calcium is withdrawn from the bones, they become weak and fragile.

Topdressing feed with oyster shell or limestone will usually reduce the incidence of cage layer fatigue in young hens. In older hens, the problem is most likely a deficiency of phosphorus and/or vitamin D3. Therefore, for older hens, topdressing the feed with dicalcium phosphate and adding a vitamin and electrolyte supplement to the hens’ drinking water may help reduce the incidence of the condition.

If affected hens do not respond to treatment, they should be submitted to a poultry disease diagnostic laboratory to determine the cause of the symptoms. There are diseases that can cause conditions or symptoms similar to cage layer fatigue.


Mineral deficiencies in poultry. Merck Veterinary Manual.