Leg and skeletal problems are a very important area especially from welfare points of view and are common in some breeds of broilers. Issues include rickets, TD, spondylolisthesis, slipped tendons, tibial rotation and femoral head necrosis.
Slipped tendon or Perosis is a metabolic disease that causes deforming leg weakness in chickens, ducks and turkeys. It is usually seen in poultry under six weeks of age, and results in flattened and enlarged hocks. This causes slippage of the Achilles tendon at the hock which causes the foot and shank to extend laterally from the body, and only appears in one leg. It is called ‘spraddle legs’ if both legs are affected, and is most often caused by injuries received when other chicks pile upon it or when the chick is placed on slick flooring soon after hatching.
Perosis is caused by a deficiency of a number of trace nutrients, primarily manganese and choline, but zinc, pyridoxine, biotin, folic acid and niacin may also be involved. In turkeys it may be an inherited galactosamine deficiency.
It is important to provide starter and grower diets that are formulated to contain adequate amounts of all trace minerals and vitamins, especially manganese and choline. Water that contains vitamin supplements will ensure that perosis does not develop in young chicks. Most perosis-affected flocks will respond to supplementation with manganese.