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Vitamin A Deficiency

Roup, Hypovitaminosis A, Follicular Hypeerkeratosis, Phrynoderma, Squamous Cell Hyperplasia

Vitamin A deficiency, otherwise known as hypovitaminosis A, is a common nutritional condition affecting chickens. It occurs as a result of malnutrition, lack of the vitamin in the diet, or as a secondary result from their body's inability to absorb or store vitamin A. Vitamin A deficiency presents as a number of different clinical manifestations, ranging from xerophthalmia (dry eye), uropygial gland infection, impaired growth, and increased susceptibility to severe infection. It affects ocular tissue in two ways: by slowing the regeneration of the visual pigments following exposure to bright light and by disrupting epithelial integrity.

Risk Factors for Vitamin A Deficiency

  • Malnourished or starved chickens.
  • Feeding chickens feed which has been stored for longer than 60 days.
  • Lack of access to fresh forage.
  • The chicken has an underlying condition that is causing an impairment in vitamin A absorption or storage.
  • Vitamin imbalances
Vitamin A nutrient interactions

Nutrition Requirements

Vitamin A Recommendations for Chickens
Age/Life StageIU/kg
Newly Hatched Chicks (0 - 10 wks)12,000-13,000
Young & Growing (10 - 20 wks)10,000-12,000
Laying hens (Actively laying eggs)8,000-12,000
Breeders (20 wks & older)*10,000-15,000
Broiler/'Meat' Breed Chicks (0-18 wks)10,000-12,000
Broiler/'Meat' Breeds* (19 wks & older)12,000-15,000
*Includes roosters

Clinical Signs

Rough, dry skin
Eye inflammation
Ruffled feathers
White-yellowish mouth sores
Pale comb and wattles
Decreased egg production
Blood spots in eggs


  • History
  • Clinical signs
  • Diet ration analysis
  • Histopathology - Presence of squamous metaplasia affecting the cuboidal and columnar epithelia of the mucosal glands of the digestive, respiratory, and urinary tracts and the eye.


Management changesIncrease access to green forage and scratching soils for insects, many of which contain high amounts of vitamin A. Purchase smaller quantities of feed so that your not feeding stale food to your flock.
Add vitamin A rich foods to rationsVitamin A food sources for chickens
Cod liver oilMixed within feed ration at the rate of 2 tablespoons per 5 lb (65 mL per 5 kg), however used sparingly.
Vitamin A20,000-33,000 U/kg IM q7dSpeer, 2016



  • Provide flock access to green forage
  • Throw away any chicken feed that is still present after a month. If needed, purchase in smaller quantities or split feed with another flock owner.
  • Make sure to properly store feed in an air-tight container, free of moisture and exposure to sunlight: This is because vitamin A content is dramatically reduced with exposure to ultraviolet light.
  • Supplement diet with dark green vegetables, yellow or orange fruits and vegetables, or fresh edible herbs which are rich sources of vitamin A (such as dandelion).

Scientific References

Risk Factors

  • Limited or no access to green forage
  • Chickens that are fed stale commercial feed
  • Improperly balanced home-mixed feed
  • Malabsorption of vitamin A by the body
  • Chicks hatched from vitamin A-deficient parents
  • Increased excretion of urine
  • Lack of storage ability of Vitamin A by the body, caused by the presence of liver disease.
  • Infectious diseases contribute to vitamin A depletion