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Vitamin K Deficiency

Vitamin K is a fat-soluble vitamin stored in fat tissue and the liver. It is best known for its role in helping blood clot, or coagulate, properly. Vitamin K also plays an important role in bone health. There are 3 forms of vitamin K.

Presentation of Vitamin K Deficiency

Chickens with vitamin K deficiency have delayed blood clotting, and will excessively bleed even with minor injuries. Sulfaquinoxaline can also cause a vitamin K deficiency in chickens, or increase the severity. Clinical signs of vitamin K deficiency usually occur from 2-3 weeks of being on a vitamin K-deficient diet. In severe cases, a lack of vitamin K will cause subcutaneous and internal hemorrhages, which can be fatal. Chickens will develop large hemorrhages on their body. Eggs from vitamin-K deficient breeders will cause increased embryo mortality late in incubation.

Vitamin K Food Sources

Foods that contain a significant amount of vitamin K include green leafy vegetables such as lettuce, cabbage, asparagus, spinach, broccoli, turnip greens, and kale. Chlorophyll is the substance in plants that gives them their green color and provides vitamin K. Freezing foods may destroy vitamin K. Vitamin K is abundant in pasture and green roughages. Green leaves are the richest natural sources of vitamin K1. Light is important for its formation, and parts of plants that do not normally form chlorophyll contain little vitamin K.

Vitamin K Recommendations in Chickens

Age/Life Stagemg/kg
Newly Hatched Chicks (0 - 10 wks)3-3.5
Young & Growing (10 - 20 wks)3-3.5
Laying hens (Actively laying eggs)2.5-3
Breeders (20 wks & older)*2.0-5
Broiler/'Meat' Breed Chicks (0-18 wks)3.0-5
Broiler/'Meat' Breeds* (19 wks & older)5.0-7
*Includes roosters

How much Vitamin K is Toxic?

The natural forms of vitamin K, phylloquinone and menaquinone, are nontoxic at very high dosage levels. The synthetic menadione compounds may be toxic at dietary levels of about 1,000 times the dietary requirement in chickens.

Clinical Signs

Thin blood
Poor clotting


  • History
  • Clinical signs
  • Laboratory tests


Vitamin K1: administered IM (0.025-2.5 mg/kg q12h): B Speers



  • Provide small amounts of herbs to diet, specifically basil, sage, thyme and/or parsley.
  • Breeder parent diets should be supplemented with vitamin K to ensure good chick health.

Scientific References

Risk Factors

  • Sulfaquinoxaline
  • Chickens with coccidiosis or other factors which affect intestinal synthesis or absorption.
  • Liver disease
  • Serious burns