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Sudden Death Syndrome

Other Names: Flip-over Disease

Sudden death syndrome (SDS), also referred to as flip-over disease, is a metabolic condition which occurs in commercial broilers and related Cornish breeds. Chickens with SDS exhibit a sudden attack just prior to death (approximately 37 to 69 seconds), characterized by loss of balance, strong muscular contractions, and violet flapping of their wings. The loss of balance and violent flapping often causes the bird to fall forwards or backwards, and may turn over onto their back or sternum during the course of the violent flapping. Some birds may give a loud squawk or high-pitched cry during the attack.

SDS occurs as a result of the excessive growth rate and high carbohydrate intake that occurs in modern day broilers. The incidence rate is typically 1 to 4%.

Clinical Signs

Sudden seizure prior to death
Bird found dead, lying on their back


  • History
  • Clinical signs
  • Necropsy


There are no treatment options.::



  • Provide a low-energy diet
  • Reduce the number of hours of light exposure per day.



Scientific References

Good Overviews

Risk Factors

  • Genetics
  • Consuming a high-energy diet
  • Males are more at risk than females.