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Vitamin E Deficiency

Other Names: Avian Encephalomalacia, Crazy Chick Disease, Hypovitaminosis E

Vitamin E is a fat-soluble vitamin and antioxidant. Naturally occurring vitamin E includes eight fat-soluble isoforms: α-, β-, γ-, and δ-tocopherol and α-, β-, γ-, and δ-tocotrienol. Vitamin E has been shown to be essential for integrity and optimum function of reproductive, muscular, circulatory, nervous, and immune systems. Vitamin E is stored throughout all body tissues, with highest storage in the liver. Vitamin E an essential nutrient for chickens of all ages, and its deficiency causes several disorders.
  • Encephalomalacia: Encephalomalacia is a serious disorder that causes permanent tissue damage to the chicken's brain, as a result of localized softening of the cerebral. This form of vitamin E deficiency occurs most often in chickens that are getting fed a diet containing high levels of polyunsaturated fatty acids of the linoleic acid series (such as that found in many cooking oils) and low levels of vitamin E. Dilauryl succinate has also been documented to induce encephalomalacia in chickens.
  • Exudative diathesis (ED): ED occurs as a result of selenium deficiency in chickens, and it primarily affects the capillary walls. Clinical signs observed include greenish-blue discoloration of the skin in localized areas of the chick's body, along with edema and hemorrhages, often resulting in bow-legged posture and pendulous (loosely hanging) crop in the throat latch area.
  • Nutritional muscular dystrophy: Nutritional muscular dystrophy, also known as white muscle disease or nutritional myopathy, is a disease that primarily affects the chicken's striated muscles. It involves progressive weakness and degeneration of the muscles that control movement. Affected chicks are often unable to stand or walk and are seen on the ground with their legs spread laterally.

Nutritional Recommendations for Vitamin E in Chickens

Vitamin E levels recommended in the Nutrient Requirements of Poultry (NRC, 1994) are extremely low and were determined solely based on enhancing productivity traits of broilers and laying hens, and not in relation to immune enhancement and long-term health and well-being. Based on latest research studies, vitamin E requirements recommended for chickens at various stages of growth include:
Vitamin E Recommendations for Chickens
Age/Life StageIU/kg
Newly Hatched Chicks (0 - 10 wks)50-100
Young & Growing (10 - 20 wks)30-35
Laying hens (Actively laying eggs)20-30
Breeders (20 wks & older)*50-100
Broiler/'Meat' Breed Chicks (0-18 wks)80-100
*Includes roosters

Clinical Signs

Torticollis (wry neck)
Muscle spasms
Greenish-blue skin discoloration
Loosely hanging crop
Inability to stand or walk
Bow-legged posture
Outstretched legs
"cycling" with legs
Reduced egg production
Poor egg quality
Reduced fertility


  • History
  • Clinical signs
  • Blood test - Serum Vitamin E levels

Reported Cases

  • Case 1: Steatitis from Vitamin E deficiency in a Heron Steatitis due to vitamin E deficiency occurred in three 10-wk-old boat-billed herons despite daily placement of a powdered vitamin supplement on the fish that was subsequently washed off by the parents. Physical findings included emaciation, yellow-brown subcutaneous nodules, a firm distended coelom, stomatitis, and yellow-white, submucosal pharyngeal nodules. Clinical pathology revealed heterophilic leukocytosis, anemia, hypoproteinemia, and low plasma alpha (alpha)-tocopherol levels (1.94 g/ml and 2.14 g/ml). Two of the chicks died of severe, diffuse pansteatitis and respiratory aspergillosis. Ref

  • Case 2: Encephalomalacia due to vitamin E deficiency in a Chickens Encephalomalacia, also called “crazy chick disease”, due to vitamin E deficiency was diagnosed in 22-day-old broiler chicks which had ataxia, paralysis, opisthotonus, torticollis and were unable to right themselves if laid on their backs. The cerebellum in a few chicks was enlarged, pale yellow and had a few petechiae. Histopathology of this organ confirmed encephalomalacia. Vitamin E levels in the liver of four birds were less than 1 ppm (Normal 3 to 15 ppm). Ref

  • Case 3: Encephalomalacia due to vitamin E deficiency in a Chickens Encephalomalacia due to vitamin E deficiency was diagnosed in 28-day-old broiler chickens from a flock of 22,000. Less than 1% of chicks in the flock exhibited neurological signs including recumbency, ataxia, paralysis and torticollis. Necropsy of chicks revealed hemorrhages in the cerebellum and cerebrum. Histopathology revealed severe malacia with intralesional thrombi. Analysis of brain and feed for vitamin E revealed deficient levels. Ref

  • Case 4: Vitamin E deficiency in a Emus Thirteen of 64 emus on a commercial emu farm in Ohio exhibited neurological signs that included backward staggering, incoordination, generalized weakness, and sitting on their hocks with head retracted backward. Eight of the birds showing such signs were found dead. Two of these emus were necropsied, and no significant gross lesions were observed. Major histopathological lesions were found in the cerebellum and included multiple malacic foci in association with neuropil rarefaction and astrogliosis within the white matter of folia. In addition, the hepatic vitamin E level of one emu was determined at the Michigan State University Animal Health Diagnostic Laboratory (MSU-AHDL) to be 14.61 mg/g dry weight. This vitamin E level was in the lower percentile (35%) of 30 emu liver samples examined at MSU-AHDL. A diagnosis of vitamin E-associated encephalomalacia was made based on clinical signs, gross and histological lesions, and liver vitamin E levels. Ref

  • Case 5: Nutritional encephalomalacia due to Vitamin E deficiency in a Turkey Nutritional encephalomalacia due to Vitamin E deficiency was diagnosed in 3-week-old turkey poults with increase in mortality (1.5% per day) in a flock of 10,000 birds. The birds were ataxic, lying in lateral recumbency and paddling. Necropsy revealed severe petechial hemorrhages on the cerebellum associated with microscopic multifocal necrosis and thrombosis. Vitamin E levels in the liver ranged between 0.53 and 2.2 ppm (normal range: 3-15 or greater). Ref

  • Case 6: Vitamin E deficiency in a Turkey Four-to-five-week-old turkey poults fed a diet markedly deficient in vitamin E (alpha-tocopherol) abruptly developed neurologic signs such as tremor, incoordination, and recumbency shortly after being moved to new quarters. Serum concentrations of alpha-tocopherol in birds on this diet were significantly lower than control values. Associated lesions included recent ischemic necrosis of the cerebellum and spinal cord. The condition closely resembled nutritional encephalomalacia of chicks. Ref

  • Case 7: Vitamin E deficiency in a Turkey. An outbreak of neurological disease in 2 1/2-to-3 1/2-week-old male turkey poults was diagnosed morphologically as nutritional encephalomalacia. About 20 to 30% of the flock of 6360 showed clinical signs, which included going down with legs extended or hock-sitting and inability to get up, incoordination, weakness, staggering, trembling, torticollis, and opisthotonus. The most important gross postmortem changes were found in the brain, which consisted of an enlarged and swollen cerebellum with focal and/or diffuse hemorrhages. Major histopathological alterations included congestion, hemorrhages, necrosis, and malacia associated with hyaline capillary thrombi affecting the cerebellar cortex and adjacent white matter. Except for a slightly higher mortality, flock performance compared favorably with performance of other flocks grown in the same farm as well as with the national average for market tom turkeys. Ref
    Primary tumor site: brainSites of Metastases:


Supportive careIsolate the bird from the flock and place in a safe, comfortable, warm location (your own chicken "intensive care unit") with easy access to water and food. Limit stress. Call your veterinarian.
Supplemental Vitamin EAdministered IM (0.06 mg/kg q7d), or orally (15 mg/kg once, without food)B Speers



  • Feed a balanced diet with proper dietary supplements with vitamin E and inorganic selenium.
  • Use only fresh feed that has been stored properly in an air-tight container, and not more than 2 weeks old
  • Don't feed vitamins that have passed their expiration date
  • Provide chickens intended for breeding a breeder feed and/or additional vitamin supplements.


Good if treated during the early stages.

Scientific References

Age Range

Signs tend to develop in young chicks between 2-6 weeks old.

Risk Factors

  • Feeding chicks starter feed that is more than 2 weeks old
  • Improperly storing feed
  • Purchasing poor quality feed
  • Feeding breeding chickens laying hen feed, without providing additional vitamins and minerals needed for breeding
  • Feeding vitamins that are past their expiration date
  • Feeding chicks a diet high in rancid fat
  • Diet lacking antioxidants