Some breeds of chicken – like the Kadaknath of India and the Ayam Cemani of Indonesia – are extremely black. Their feathers, beaks, skin, meat, internal organs, and even bones are black.

You may have heard of the Silkie breed of chicken, big fluffy white chickens that have black skin, blue ears, and extra toes. Marco Polo was an early fan. Well, a couple of other breeds of chicken, probably genetically related to the silkie, are even blacker.
The Ayam Cemani originated in Java (the name translates as “chicken from Cemani” – Cemani being a village on the island); the Kadaknath from Madhya Pradesh in India. Because of a genetic mutation these breeds are suffused with an extremely excessive amount of melanin. The result: a completely black bird, inside and out. The feathers, beak, eyes, tongue, and skin are all black (although the Kadaknath sometimes has a rather greenish tinge). Cut one open and the meat and organs are also black, or perhaps a rather dark grey if you’re lucky.
Even, and this is quite incredible to me, the bones of these chickens are black. It’s rather hypnotic to see one walking around, like someone cut a chicken-shaped hole in the screen:
[Thanks to Cristina G. for suggesting this topic.]