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Slipped Tendon

Slipped tendon is a generalized skeletal disorder that causes leg deformities in young, rapidly growing chicks. The condition can be the result of a nutrient deficiency or an inherited defect in many chicken breeds that are raised for food purposes. It involves the growth plate of the long bones, resulting in the development of short, thickened, misshapen long bones that are frequently accompanied by an enlarged hock joint and relocation of the tibiotarsal end of the bone.

Slipped tendon is a significant cause of lameness in broiler chickens. Affected chickens are often seen in a hock sitting position with their toes directed ventrally. In severe cases, the bird's Achilles tendon slips from the groove formed by the condyles of the tibia, pulling the leg out of shape to appear very crooked (valgus deformity). When both legs are affected, it results in bowing of the legs (varus deformity). Increased incidence has been associated with rapid growth rate of modern heavy chicken breeds, mineral/vitamin deficiencies, infrared brooding, and exposure to certain toxins.


Swelling and flattening of the hock joint
Displaced, twisted leg
Hock-sitting posture
Reluctance to move


  • History
  • Clinical signs
  • Physical exam
  • Radiography


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.
VitaminsSupplementing the chicken's diet with manganese, zinc, vitamin E, niacin, biotin, folic acid, pyridoxine and choline


  • Ensure chickens receive a balanced diet with adequate amounts of manganese, zinc, vitamin E, niacin, biotin, folic acid, pyridoxine and choline.
  • Ensure chickens receive a diet with appropriate calcium to phosphorus ratio

Scientific References

Age Range

It affects males more than females, older than 7 weeks of age.

Risk Factors

  • Vitamin/mineral deficiencies involving manganese, zinc, vitamin E, niacin, biotin, folic acid, pyridoxine or choline
  • Extreme temperature fluctuations during incubation
  • Poor ventilation in incubator

Also Consider