Fibromelanosis, often shortened to “fibro,” is the word used to describe the black hyperpigmentation found in a handful of chicken breeds. The Ayam Cemani and the Silkie are two of the most popular breeds found in the United States that exhibit this trait. Chickens with fibromelanism are quite popular in Asian countries and there are many more breeds available with fibromelanism in that region of the world.
How did we get Fibro Chickens?
The fibromelanosis gene causes an excessive amount of melanin to accumulate in the dermis (skin) and connective tissues of the chicken. This gene is believed to be a dominant gene, so if a hyper-pigmented male is mated with normally pigmented females, some of the resulting chicks will display this dark hyperpigmentation that their father possessed. By continually selecting the darkest chicks and breeding them to other fibromelanistic birds, the resultant coloring will become more consistent and stable over several generations. It is even possible to create hybrids that display fibromelanism, such as the Fibro Easter Egger.
Even though the gene responsible for the black coloration in fibromelanistic birds is thought to be dominant, the resulting "blackness" that any single bird exhibits can vary because the gene may or may not be fully expressed. Ayam Cemani birds tend to have "extreme" exhibition of the fibromelanism gene. While Silkies and other breeds or hybrids with the fibro gene may show some "dilution" of the degree of black pigmentation.
Breeds With Fibromelanosis
In the Ayam Cemani, you will typically find that every part of the bird is jet black, inside and out. For most of us in America, that can be a bit shocking and perhaps off-putting if we intend to use this breed for meat. The comb, wattles, legs, inside of the mouth, beak, eyes, ear lobes, bones, and internal organs are all solid black; however, the Ayam Cemani hens lay a cream-colored shell with a normally colored yolk and white.
In the Silkie, the fibromelanosis is expressed to a lesser degree than in the Ayam Cemani. Silkies will typically have colorful feathers. In fact, they come in several different color varieties recognized by the American Poultry Association. Silkies also may have varying degrees of black pigmentation in the inside of the mouth and on their combs, wattles, and earlobes. They typically have black skin, feet, and legs, but the richness of the color may vary from bird to bird. Silkies lay pale cream-colored eggs.
The Fibro Easter Egger is perhaps one of the most exciting fibromelanistic hybrids found today. The degree of black feathering with Fibro Easter Eggers will vary but the skin, legs, and lobes should be black colored. Because this is a hybrid, subsequent generations may have varying degrees of pigmentation. The Fibro Easter Egger usually lays a blue or blue-green egg.