Ayam Cemani

Fibromelanosis is a genetic condition in chickens characterized by hyperpigmentation of connective tissues, resulting in black skin, muscles, organs, and bones.

This trait is caused by a duplication near the endothelin 3 (EDN3) gene, which leads to increased expression of melanin-producing cells (melanocytes) throughout the body—not just in the skin.

Found prominently in breeds like the Silkie, Ayam Cemani, and Kadaknath, fibromelanosis is inherited in an autosomal dominant pattern.

While it does not affect the chicken’s health or productivity, the striking black coloration is highly valued for its rarity, cultural significance, and in some regions, perceived medicinal properties.