They have a dominant gene that causes hyperpigmentation (fibromelanosis), making the chicken mostly black, including feathers, beak, and internal organs.

The Cemani is a very popular gamecock for cockfighting in Bali because their thighs have much more muscle compared to other chickens, which leads to them being much faster.

[citation needed] Currently, this breed of chicken is kept in the Netherlands, Belgium, Germany, Slovakia, Sweden, Italy, America and the Czech Republic.

The birds' black color occurs as a result of excess pigmentation of the tissues, caused by a genetic condition known as fibromelanosis.

The hens lay tinted or cream-colored eggs, although they are poor setters and rarely hatch their own brood.