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The ISA Brown is a hybrid type of Sex Link chicken. It is thought to have been the result of a complex series of crosses including but not limited to Rhode Island Reds and Rhode Island Whites, and contains genes from a wide range of breeds, the list of which is a closely guarded secret. The ISA Brown is a hybrid, not a true breed, developed by breeding unrelated "dam" and "sire" lines together until the final result. It is known for its high egg production of approximately 300 eggs per hen in the first year of laying.
|Other names||Hubbard Brown, Brown, Red Sexlinks|
|Country of origin||France|
ISA stands for Institut de Sélection Animale, the company which developed the hybrid in 1978 for egg production as a battery hen. In 1997, the ISA Group merged with Merck & Co., forming Hubbard ISA,  so the hybrid is sometimes called Hubbard Isa Brown. In 2005, Institut de Sélection Animale (ISA) and Hendrix Poultry Breeders (HPB) merged in ISA B.V., which also became part of the multi-species breeding company, Hendrix Genetics. In March 2005, Hubbard was purchased from Merial Ltd by Group Grimaud La Corbiere, SA.