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Professional Version

Fatty Liver Hemorrhagic Syndrome in Laying Hens


Rodrigo A. Espinosa

, DVM, DACPV, Aviagen

Reviewed/Revised Jan 2024
Topic Resources

Fatty liver hemorrhagic syndrome (FLHS) occurs more in commercial layers and occasionally in broiler breeders.

FLHS is more common after 35 weeks with overweight birds characterized by decreased production and sudden death of birds in production.

At necropsy, clotted blood can be observed in the abdominal coelom, around and originating from the liver, which is pale and friable (see ). A fatty liver is a noninfectious metabolic disorder, resulting in liver rupture, hemorrhaging, and increased hen mortality.

At the onset of sexual maturity, the liver contributes actively to sourcing the lipids for the developing follicles. Thus it is considered a critical component of the reproductive system in laying hens; a healthy liver is key for high egg production.

Key factors in controlling the disease include the following:

  • preventing excess body weight by controlling excess energy and protein consumption in the critical period of 22–30 weeks (to avoid excess positive energy balance during this period)

  • providing a balanced diet limiting the presence of mycotoxins

  • controlling house temperature during hot and humid summer conditions

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