The Differences Between Ayam Cemani & Svarthona Chicken Breeds

To the untrained eye, the Ayam Cemani and the Svarthona appear nearly identical. Both are striking black chickens with dark feathers, skin, and eyes. Their all-black appearance sets them apart from most poultry breeds and has earned the ayam cemani a place in the world of rare and exotic chickens. However, beneath the surface, the two breeds differ significantly in origin, genetic expression, physical characteristics, and practical use.

Although they share a genetic condition known as fibromelanosis, which causes hyperpigmentation, the Ayam Cemani and Svarthona are not the same breed. Each has been shaped by different environments, breeding goals, and cultural influences. This article explores those differences in detail.

The Ayam Cemani originates from Indonesia, specifically the island of Java. It has long been a part of Javanese folklore and spiritual tradition. In local culture, Ayam Cemani chickens are believed to possess mystical powers and are sometimes used in ceremonial rituals, particularly for their dark physique (inside and out) which is thought to hold spiritual energy.

The name "Ayam" means "chicken" in Indonesian, while "Cemani" is believed to derive from a Javanese word meaning "completely black", referring to the bird’s striking full-body pigmentation. The breed is believed to have originated in Central Java, particularly in regions such as Kedu.

In contrast, the Svarthona developed much farther north, in Scandinavia. This breed is the product of fibro melanistic chickens, possibly including Ayam Cemani, that were brought to Norway and Sweden by sailors or traders. These birds were then selectively bred to survive and thrive in cold northern climates. Over time, they became a distinct breed, now known in English as the Swedish Black Hen. Unlike the Ayam Cemani, the Svarthona was not bred for religious or cultural significance but rather for practical farm use.

Both breeds owe their black coloration to a dominant mutation linked to fibromelanosis, caused by a duplication near the endothelin-3 (EDN3) gene. This gene controls the overproduction and migration of melanocytes, the pigment cells responsible for melanin. As a result, affected birds show black pigment not only in their feathers and skin but often throughout their entire bodies.

However, the intensity and consistency of fibromelanosis differ between the two breeds. The Ayam Cemani typically expresses the gene in its homozygous form (FM/FM), which results in uniform and intense pigmentation. This includes black feathers, skin, dark eyes, beak, tongue, internal organs, muscles, and even bones. In Indonesia, and among specialty breeders worldwide, birds are selectively bred to maintain and enhance this extreme pigmentation.

The Svarthona also carries the fibromelanosis gene, but its expression is usually less extreme. Many individuals have heterozygous expression (FM/+), and as a result, pigmentation can be inconsistent. While most Svarthona have black or dark gray skin, feathers, and combs, their tongues may appear gray or pink, and their internal organs may show little to no pigmentation. Breeders in Scandinavia have historically prioritized hardiness and egg production over perfect pigmentation, which contributes to the genetic variability seen in this breed.

Externally, both the Ayam Cemani and the Svarthona appear strikingly black, with a glossy iridescent sheen that can reflect green or purple in sunlight. Their skin, wattles, combs, and legs are all dark in color, typically black or dark slate. However, Ayam Cemani chickens tend to be more uniform in pigmentation across every visible trait, including black tongues and fully pigmented feet and nails. Svarthona may show lighter-colored claws or less saturated areas on the beak or tongue.

Internally, the difference becomes more pronounced. The Ayam Cemani is famous for its deep internal melanization. The meat is dark gray to black, and the organs, such as the heart, lungs, liver, and reproductive tract, are also heavily pigmented. Even the bones are black or bluish gray. This trait is highly sought after and is one of the breed’s defining features.

The Svarthona, on the other hand, usually exhibits partial internal pigmentation. While some birds may have dark meat or organs, others are internally similar to conventional chickens. This inconsistency reflects the breed’s utility-focused history and the more relaxed approach to maintaining extreme pigmentation.