Cage fatigue of layer chicken

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 As more and more calcium is withdrawn from the bones, they become weak and fragile.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 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.

cage layer fatigue syndrome in birds is characterized by an inability to stand on their feet and fragile bones. It is mainly observed in young layer hens reared in batteries in the period of maximum egg-laying. Affected birds lie down and stopped eating. Egg shells become thin.

The calcium deficiency is layer hens results in initial removal of calcium from bones, to complete depletion of the medullary bone and thereafter, of the bone wall. The bones are strongly thinned and spontaneous fractures, especially of the tibia and the femur could occur. Although the severe calcium deficiency is often a triggering factor, the aetiology of the syndrome seems to involve other, yet unknown factors. The supplementation of calcium, phosphate and multivitamin preparations in the diet and rinking water, the regulation of avian population density into cages and ensuring adequate nutritional and drinking fronts are also contributing for the favourable outcome of the condition.