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Vitamin B12 Deficiency

Vitamin B12 , also called cobalamin, is one of 8 water-soluble B vitamins. Vitamin B12 is an essential part of several enzyme systems that carry out a number of basic metabolic functions. Vitamin B12 is necessary for the formation of DNA and the production of red blood cells. It helps maintain the nervous system and is essential to maintaining mental function. Vitamin B12, along with B6, and folate, is essential to heart health. Folate and B12 work together to produce S-adenosylmethionine (SAMe), a compound involved in immune function and mood.

Vitamin B12 Deficiency

Chickens with vitamin B12 deficiency usually develop clinical signs associated with nervous system impairment, such as leg weakness and perosis. Other signs include poor feathering and reduced hatchability from deficient breeding parents. Vitamin B12-deficient embryos die at about day 17.

Vitamin B12 Deficiency Risk Factors

  • Intestinal malabsorption
  • : Includes gastrointestinal conditions affecting the chicken's small intestine.
  • Decreased stomach acid production
  • : Provides an ideal environment for the overgrowth of anaerobic bacteria in the bird's stomach, which further interferes with vitamin B12 absorption.

Sources of Vitamin B12

Commercial sources of vitamin B12 are produced from fermentation products, and it is available as cyanocobalamin. Vitamin B12 is only slightly sensitive to heat, oxygen, moisture and light.

Nutritional Recommendations for Vitamin B12 in Chickens

Age/Life Stagemg/kg
Newly Hatched Chicks (0 - 10 wks)0.025-0.03
Young & Growing (10 - 20 wks)0.02-0.025
Laying hens (Actively laying eggs)0.015-0.025
Breeders (20 wks & older)*0.02-0.04
Broiler/'Meat' Breed Chicks (0-18 wks)0.02-0.03
Broiler/'Meat' Breeds* (19 wks & older)0.03-0.04
*Includes roosters

Feeding Too much Vitamin B12

Vitamin B12 is relatively nontoxic when fed in high amounts. Dietary levels more than 100 times the requirement have been shown safe in most animals.

Clinical Signs

Stunted growth
Loss of appetite
Poor feather quality
Reduced egg size
Decreased hatchability


  • History
  • Clinical signs
  • Dietary analysis


Vitamin B12 : Administered IM (0.25-0.5 mg/kg q7d) or SC (2-5 mg/bird): B Speers



Provide chickens a balanced diet with appropriate amounts of B vitamins

Scientific References

Risk Factors

  • Feeding chickens a poor quality diet
  • Improperly storing chicken feed.