Calcium and Phosphorus Deficiency o ...

Calcium and Phosphorus Deficiency or Imbalance in Laying Hens

Calcium and Phosphorus Deficiency or Imbalance in Laying Hens

 Calcium (Ca) and Phosphorus (P) is closely associated with metabolism, particularly in bone formation. The major portion of dietary calcium is used for bone formation in growing chicks or poults and for eggshell formation in mature hens. (1, 2)

In laying hens, calcium deficiency results in reduced egg production and thin-shelled eggs as well as a tendency to deplete calcium content of the bones, first by complete removal of medullary bone, followed by gradual removal of the cortical bone.  Finally,  bones become so thin that spontaneous fractures may occur, especially in vertebrae, tibia, and femur. (1, 2)

Although a marginal calcium deficiency has often been found to be triggering agent in cage layer fatigue, the syndrome apparently is not due to a simple deficiency of calcium but also involves other etiologic factors not yet identified. (1, 2)

The utilization of calcium and phosphorus depends on the presence of an adequate amount of vitamin D in the diet. In vitamin  D deficiency, the deposition of these minerals in bones of growing chicks and poults is reduced;  bones become depleted of mineral, and the quantity of calcium in eggshells is decreased. (1, 2)

Marginal calcium deficiency has often been found to be a triggering agent in cage layer fatigue. (1, 2). Osteoporosis more severe between 25 and 50 weeks of age. (1, 2)

 Clinical signs of Cage Layer Fatigue are exclusively seen in layers housed in cages. (1, 2)

  Observed Clinical Signs happenings

Egg drop

  • Egg production drops gradually
  • In laying hens, calcium deficiency results in reduced egg production and thin-shelled eggs

Egg quality

  • Thin-shelled and soft-shelled or porous eggs
  • May increase the incidence of thin-shelled eggs
  • Calcium and phosphorus deficiency results in reduced egg production and thin-shelled eggs
  • Ungraded or second's eggs increased
  • Egg specific gravity score lower (should be above 1.080 (1.068 thin shells)

Diet or Feed Changes

  • Recent Feed delivery
  • Recent formulation / diet
  • Sometimes it is difficult to find a relationship with the diet or feed origin

Calcium and Phosphorus Deficiency or Imbalance in Laying Hens  DOES NOT exhibit or manifest any of the following clinical signs happenings:

  • Egg production declines rapidly
  • Mortality above the standard
  • Visibly sick birds
  • Flock behaviour activity change
  • Droppings abnormalities
  • Respiratory abnormalities
  • Neurological Nervous
  •  Lameness or unusual movements, incoordination, reluctance to move
  •  Eyes abnormalities
  • Head, Comb, Wattles, Face, Nostrils, Sinuses, Mount, Beak, Earlobes, abnormalities (except eyes)
  • Body Parts (Neck, wings, breast, abdomen, shanks, legs, hocks, feet, joints, vent, and skin, abnormalities), skinny body, retarded growth, weight depression
  • Feathers abnormalities
  • Feed Consumption Changes
  • Internal Egg defects
Causing Agents
Calcium (Ca) and Phosphorous (P) deficiency or imbalance in the diet. Decreased of normal mineralization of structural bone and egg-shell. According to Long et al. phosphorous deficiency (0.2% available dietary P) and calcium excess (2.24% Ca and 0.45% available P) resulted in similar abnormalities of the tibia. Birds die of right ventricular failure, often accompanied by ascities. Calcium and phosphorous are closely associated in metabolism processes, particularly in bone and eggshell formation.
Affected Systems/Organs
Reproductive and locomotor systems
Mainly Affects
Egg production, egg quality and performance
Supplementation of the diet with Vitamin D and appropriate Ca and P ratio and levels. The availability of phosphorous can be increased by inclusion in the diet of phytase of microbial or plant origin. The phosphorous in plant-base feedstuffs is poorly available because much of it is present in phytic acid and is not released by digestive enzymes.
Suggested Actions
  • Can be confirmed with clinical signs and gross lesions
  • Technical assistance recommended
  • Can be managed with feed additives, off-the-shelf medications
  • Diagnosis should be confirmed with rapid assays and/or a certified laboratory
  • Veterinary intervention is recommended

Impact on Egg quality


Impact on Liveability


Impact on Production


Overall Economic Impact


Y.M. Saif. 2008. Disease of Poultry. 12th Edition. page 1137,1157

David E. Swayne. 2013.  Diseases of Poultry 13th Edition. page 1222,1240

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