Chicken Feather Patterns
Barred, Cuckoo, Mottled, Splash: common feather patterns and the genetics behind them.
Reading Time: 5 minutes
What distinguishes the chicken feather patterns barred, cuckoo, mottled, and splash? And why is the barring stronger in a Barred Rock rooster vs hen?
All feathers start as small, living organs. There are numerous layers and parts to each feather. The new feather contains a small artery in the middle and several veins, all responsible for supplying blood, oxygen, and nutrition to the newly-forming “feather-organ.” Each feather will eventually mature, then die and fall off at some point in the bird’s life. A new feather develops from the follicle to replace it. This can happen just a few feathers at a time, which is an almost imperceptible change, or may occur en masse when a bird or domestic fowl undergoes a seasonal molt and loses many feathers in a short time. One very interesting thing that any veteran poultry breeder can tell you is that the color hues of a bird’s feathers and slight variations in the actual patterns can happen when the new feathers grow back. Birds, including domestic poultry, are covered with an array of different types of feathers, each serving a distinct role in the bird’s survival, functioning, and health.
Heredity and genetics highly regulate feather color and patterns, some of which are sex-linked. Several readers asked for an article on the basic genetics behind such patterns and the difference between barred, cuckoo, and splash versus mottled. In this article, we will take a look at these.
Barred and Cuckoo Chicken Feather Patterns
The barred or cuckoo pattern in chickens … those beautiful little birds we see, with the horizontal black and white stripes, or “bars,” going around their bodies, have been one of the favorites of poultry keepers for at least 300 years. These birds, often referred to as “Dominickers,” are peppered throughout early American and colonial history. Breeds include Barred Rocks, Cuckoo Marans, Scott’s Greys (found mainly in the United Kingdom), Barred Cochins, and Dominiques. The barring gene is dominant and is sex-linked. This means it is attached to the male sex chromosome (called the Z chromosome by scientists). Male birds have two male sex chromosomes (written as ZZ), and female birds have one Z chromosome plus a smaller, female chromosome, called the W chromosome (often shown as ZW in scientific writing).
As the gene for barring is dominant (designated by the symbol B), only one gene is necessary for this chicken feather pattern to dominate the plumage. Female barred birds carry one B gene, and males carry either one or two, depending on whether they are purebred or mixed with something else. Roosters with two barring genes (BB) often have crisper, sharper barring on the plumage than those with only one barring gene (B), although both will have barred or cuckoo plumage.
What is the exact difference between “barred” or “cuckoo,” since they both come from the same genetic origins? In the United States, the term barred refers to plumage that has clean, sharp, distinct bars or lines. The term cuckoo often refers to patterns that are not as sharp and distinct, might be somewhat murky, or have uneven edges to the barring on the feathers. One prime example is Barred Rocks which have sharper, cleaner lines or bars, versus Dominiques, which have more murky, less defined lines. In some other regions of the world, the term cuckoo refers to barring in general, so even in poultry circles, you will run into national and regional terms that may be different.
Does barring and cuckoo only come in black and white patterns? There are several different color patterns currently found in barred birds. One beautiful example is the Lemon Cuckoo chicken feather pattern found in Lemon Cuckoo Niederrheiners, an old and rare breed from the lower Rhineland of Germany and the Netherlands. The color pattern consists of gorgeous, tangerine-yellow stripes alternating with white stripes. Another pattern is chocolate barring, which has its own interesting twists for breeders, as the chocolate gene in poultry is also a sex-linked gene but is recessive.
Splash and Mottled Chicken Feather Patterns
If you took a big paintbrush, dipped it in paint, and flung the paint at your chickens, you might get something remotely akin to these feather patterns. Unlike barred and cuckoo, mottled and splash plumage have separate genetic origins and should not be confused with each other.
Mottled birds have randomly applied white blotches on the tips of darker feathers (generally black, but it can include other colors), blocking out darker pigmentation in these areas. The mottling gene is recessive (designated by the letters mo), so two genes are needed for mottling to occur. The mottling gene is quite variable in the way it expresses itself. Not all feathers are mottled. Wings often show more mottling than body feathers. Mottling may be very random over the bird’s body. Breeders who raise show-quality mottled breeds work long and hard at selective breeding for many years to bring their flocks to near perfection. This one pattern takes dedication and patience to perfect, but a flock of well-mottled fowl can be very stunning. Mottling has been introduced to many breeds. Some beautiful examples include Anconas, Mottled Houdans, Mottled Javas, and Mottled Orpingtons.
Splash feathering is grey, blackish-grey, and black splotches randomly splattered over white plumage. It is controlled by two recessive “splash genes” (designated as bb). When these genes are crossed with birds having an incompletely dominant black gene, the resulting offspring holding the genes Bb will be a slate-grey color, known as “blue.” (This is designated by B for a single gene or BB if two genes are present, but do not confuse this with the B or BB gene for barring — the same letter, but different genes.) This blue does not breed true. A fowl with BB or two black genes, crossed with a bb or splash fowl, will, in theory, produce nothing but the slate-grey, “blue” offspring (Bb). Crossing two “blue” fowl will result in 50% of the offspring being blue (Bb), 25% will be black (BB), and 25% will have the splash pattern (bb). Blue Andalusians, an old Mediterranean breed similar to Leghorns in size and temperament, were one of the first breeds studied, almost 100 years ago, that helped geneticists understand the working of these color patterns in chickens. Today, many beautiful blue and splash varieties of poultry breeds hold these genes in their genotypes, including the Andalusians, Jersey Giants, Orpingtons, and Cochins.
There is also another slate-grey color called lavender. Two recessive genes control this (designated as lav). They look similar to the birds with the slate-grey “blue” color, but crossing two lavender birds gives all lavender offspring. There are many breeds with lavender varieties, including Orpingtons, Ameraucanas, Belgian Bearded d’Uccles, and Silkies.
With approximately 23,000 known genes comprising the chicken genome, the chicken feather pattern possibilities are almost endless. The variations in the plumage of individual birds, especially mixed offspring, can be infinite. Just another reason so many of us become so addicted to keeping these personable little creatures.
Originally published in the October/November 2021 issue of Backyard Poultry and regularly vetted for accuracy.