Ayam cemani breeder eating Iron food

Their beaks, tongues, combs and wattles appear black, and even their meat, bones, and organs are black or gray. Their blood is normally colored. verification needed The birds' black color occurs as a result of excess pigmentation of the tissues, caused by a genetic condition known as fibro melanosis . Fibro melanosis is also found in some other black or blue-skinned chicken breeds, such as the Selkie.

The roosters weigh 2–2.5 kg (4.4–5.5 lb) and the hens 1.5–2 kg (3.3–4.4 lb). The hens lay cream-colored eggs, although they are poor setters and rarely hatch their own brood. Eggs weigh an average of 45 g (1.6 oz).