Chicken Colour Genetics Glossary · Chicken Color Standards

Definitions for the terms used across this site. Each entry links to a fuller explanation — most into the Genetics Guide, which walks through the whole system in order. If you want the narrative rather than the dictionary, start there instead.

Descriptions and categorisation of recognised chicken colours are informed by chicken-colors.info, which provides a comprehensive, publicly accessible colour reference. Genotype associations draw on and are checked against Kippenjungle.nl. These two sources map colour phenotypes to associated genotypes. Using established methods of biological and economic modelling, Chicken Color Standards also works in the other direction: it combines individual genetic components into resulting genotypes and, when a known combination appears among calculated outcomes, connects it back to the recognised phenotype. Like any evolving model, it may still contain errors, edge cases, and areas for improvement. See the Genetics Guide for a more complete genetics reference, including the scientific background and notes on areas where published sources disagree or evidence remains unsettled — areas where chicken lovers like you can contribute to new understandings.

Jump to: Core concepts · Inheritance · Colour loci · Patterns & phenotypes

Core concepts

Eumelanin: The pigment that produces black and dark-brown colour in a feather. A large share of colour genes act by moving, restricting, or diluting eumelanin. In the guide →
Pheomelanin: The pigment that produces red, gold, and buff. It shows as the "ground colour" wherever eumelanin has been kept out. In the guide →
Gene: A stretch of DNA with a specific job — here, a job affecting where and how pigment is deposited.
Locus (plural: loci): The physical place on a chromosome where a gene sits. "Locus" names the location and gene; "allele" names a specific version found there. In the guide →
Allele: One version of a gene. A bird holds two alleles at every autosomal locus — one inherited from each parent. At the Blue locus, for example, Bl and bl+ are two alleles.
Genotype: The actual pair of alleles a bird carries at a locus (e.g. Bl/bl+).
Phenotype: What the bird actually looks like. Two birds can share a phenotype while carrying different genotypes — a central reason breeding results can surprise you. In the guide →
Wild-type: The ancestral reference allele at a locus, written with a "+" (e.g. e+, bl+). A notation baseline — not necessarily the commonest allele in a modern breed.
Ground colour: The underlying pheomelanin colour of a feather, over which any pattern of eumelanin is laid.

Inheritance terms

Homozygous: Carrying two matching alleles at a locus (bl+/bl+ or Bl/Bl).
Heterozygous: Carrying two different alleles at a locus (Bl/bl+). A recessive allele can travel hidden in a heterozygote.
Hemizygous: Carrying only a single copy of a gene. Because hens are ZW, they are hemizygous for every sex-linked (Z-linked) gene — whatever sits on their one Z is what they show. In the guide →
Dominant: An allele that shows its effect with just one copy. "Dominant" describes how many copies are needed to see it — not that the allele is stronger or better. In the guide →
Recessive: An allele that shows its effect only when both copies are present.
Incomplete dominance: Inheritance in which the heterozygote is visibly intermediate rather than matching one homozygote. Blue is the classic case: black → blue-grey (one copy) → splash (two copies), giving a 1:2:1 ratio. In the guide →
Autosomal: On a chromosome other than the sex chromosomes (Z/W); inherited the same way by both sexes.
Sex-linked (Z-linked): On the Z chromosome. Roosters are ZZ and hens are ZW, so these genes are inherited differently by sons and daughters — the basis of colour-sexing. Sex-linked genes page →
Epistasis: When one gene's visible effect depends on the alleles present at another gene — for example, a pattern gene meaning different things on different Extension bases. It is the main reason a gene cannot be read in isolation. In the guide →
Punnett square: A grid of every allele combination two parents can pass on, used to read expected offspring ratios. The Breeding Outcomes tool builds these for you.
F1 / F2: F1 is the first-generation offspring of a cross; F2 is the next generation, from crossing two F1 birds — where recessives masked in the F1 can reappear.
Linked genes & recombination frequency: Genes close together on one chromosome are usually inherited together; the recombination frequency is the chance a crossover separates them. The Db–Ml–Pg group is linked (≈0.10 Db↔Ml, ≈0.10 Ml↔Pg). In the guide → · Linked genes page →

Colour loci

The genes the Compare and Breeding tools work with. Verified molecular gene identities are noted where established; see the guide's references for sources.

1. Base and pattern structure

These establish the starting black/gold balance, then restrict, deepen, organise, or extend pigment into the main pattern carried by the bird.

E — Extension: The master control for the black/gold balance, and the base every variety starts from. It carries a whole series of alleles ranked E > E^R > E^Wh > e+ > e^b (extended black, birchen, wheaten, wild-type duckwing, brown/partridge). Its gene is MC1R. In the guide →
Co — Columbian: Sweeps eumelanin off the body, confining it to the hackle, tail, and wing tips — the "Light"/Columbian look. In the guide →
Db — Dark Brown: Deepens the pheomelanin ground toward darker ocher and red-brown shades. One of the linked Db–Ml–Pg group. In the guide → · Linked genes page →
Pg — Pattern gene: Organises eumelanin into structured markings. Its result depends on context: with e^b+Co it gives lacing, with e^b+double Ml double lacing, and with E^R spangling. A textbook case of epistasis. In the guide →
Ml — Melanotic: Pushes eumelanin further through the plumage, darkening the bird. Part of the linked Db–Ml–Pg group. In the guide → · Linked genes page →

2. Feather markings

These create repeated light marks within or at the edge of individual feathers, after the broader base and pattern structure are in place.

B — Barring (sex-linked): Lays repeating transverse white bars across each feather — the cuckoo/barred pattern. Its gene is CDKN2A/B. In the guide →
Mo — Mottling: A recessive (mo/mo) that tips feather ends with white V-shaped spots — the basis of mille fleur and mottled varieties.

3. Pigment inhibition and white routes

These determine whether black pigment, all pigment, or the inhibition of gold remains active. Dominant and recessive white reach a similar visible result by different genetic routes.

I — Dominant White: Inhibits eumelanin with a single copy, turning a coloured base largely white; layered on a Blue/Splash base it gives the "Paint" pattern. Its gene is PMEL17. Unrelated to recessive white. White genetics page →
C — Recessive White: A recessive that blocks pigment when present in two copies, reaching white by a completely different route than Dominant White (its gene is tyrosinase, TYR). Two white birds are not necessarily "the same" underneath. White genetics page →
Ig — Inhibitor of Gold: With two copies (ig/ig) it allows a gold or buff ground to show.

4. Named pigment dilutions

These replace an otherwise dark or richly coloured result with a recognisable diluted colour. They differ in which pigment they affect and how they inherit.

Bl — Blue: Dilutes eumelanin with incomplete dominance: one copy gives blue-grey, two copies splash. Leaves pheomelanin untouched. Blue, Splash & Black page →
Lav — Lavender (self-blue): A recessive that dilutes both pigments evenly — pale grey where black would be, straw where gold would be. That both-pigment action is the key difference from Blue. Its gene is MLPH. Lavender page →
Choc — Chocolate (sex-linked): Dilutes eumelanin to a warm chocolate brown. Its gene is TYRP1. Chocolate page →

5. Tone and ground-colour modifiers

These make the finished colour warmer, paler, greyer, creamier, gold, or silver. Their targets differ: some act on black, some on gold, and some on both pigments.

Mh — Mahogany: Intensifies pheomelanin into a deep mahogany red.
Di — Dilute: Dilutes both pigments, lightening the whole bird.
Cha — Charcoal: Dilutes eumelanin toward a dark grey.
Cb — Champagne Blond: Lightens pheomelanin toward pale buff or cream.
S — Silver / Gold (sex-linked): The S allele suppresses pheomelanin, replacing a gold ground with silver/white. Its gene is SLC45A2. Being Z-linked, it behaves differently in the two sexes. In the guide →

Patterns & phenotypes

The visible results — the words that describe how pigment is arranged on the finished bird, and that appear throughout the Compare tables.

Self / solid: A single, even colour over the whole bird, with no pattern — e.g. self-black or self-blue (lavender).
Partridge: The brown-based (e^b) pattern: a gold/brown ground with black restricted to markings and feather detail.
Duckwing: The wild-type (e+) pattern of the ancestral jungle fowl, with its characteristic black-and-gold distribution.
Birchen: A largely black bird (E^R base) with restricted silver or gold left in the hackle and saddle.
Wheaten: An E^Wh-based pattern in which gold dominates — strikingly so in the hen, while the rooster keeps black in breast and tail.
Columbian: The clean pattern produced by the Co gene: a white or gold body with black confined to hackle, tail, and wing tips.
Barred / cuckoo: Repeating transverse white bars across each feather, produced by the sex-linked B gene ("cuckoo" is the term for the softer-edged version).
Lacing: A clean dark border of eumelanin running around the edge of a feather of ground colour. Double lacing has two concentric borders. Pattern genes page →
Pencilling: Several fine, concentric lines of eumelanin across each feather, as in Partridge Wyandotte hens.
Spangling: A single dark spot or crescent at the very tip of each feather.
Mottling: White V-shaped tips on the feathers (from mo/mo); combined with a coloured ground it gives mille-fleur-type patterns.
Blue: The one-copy Bl phenotype: eumelanin diluted to an even blue-grey, gold areas unchanged.
Splash: The two-copy Bl phenotype: a pale bird irregularly flecked with blue-grey.

Put it to work: Compare two standards · calculate a cross · read the Genetics Guide