Self Colors: Extended Black
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By Craig Bordeleau – We all know that there is a litany of colors that ducks and backyard chickens can display. Many are complex; some so intricate they become indistinguishable from others to an untrained eye. There is a grouping of colors that are very simple to define as the birds that display them are, for the most part, a single solid color. These are called self-colored. The most common of these is extended black — it causes birds to have completely black feathers and often a gorgeous green sheen when viewed in good lighting. This particular plumage is the base for two other self-colors — blue and silver, which are not possible without the presence of extended black.
All three can also display white bibs when in conjunction with the genes responsible for that. The same goes for self-chocolate, lavender, and lilac. All of these colors will be broken down and explained in their own respective articles. This article will focus mainly on how extended black works in ducks but the genetics for this are essentially the same in black skinned chickens, and the information contained within can be applied to both species of fowl.
Although it may not be observable, completely black birds do have a genotypical pattern. It becomes obscured by black extending the length of the feathers rather than being limited to certain areas. The black is already present, and the extending gene does not allow for the expression of pattern. This is why it is fairly easy to breed into any poultry strain regardless of its traditional plumage.
The gene is incompletely dominant, meaning only one of the two alleles responsible for making up the gene needs to be extended black for it to show. Effectually, if you breed a black bird to a non-black bird, all or half of the resulting offspring should be black. If one parent has a fully dominant extension (represented as E^e,E^e) all progeny will carry one of the necessary alleles. If that parent has just one (E^e,E^+), statistically, only half of its progeny will carry and display the gene. The other half would be subject to whatever rules govern the pattern or patterns mixing. For ducks to display self-black, two non-wild type genes must be present — the dusky pattern and the extended black itself. The dusky pattern obscures the wild eye stripe, neck ring, and coloration of the speculum. This makes it possible to cover the entire bird with one solitary color.
There are a couple of things that go along with having a completely black bird. The most notable being the green sheen. It is caused by prisms within the feathers refracting light so that the plumage appears to be a shiny green rather than black. It isn’t caused by any sort of color gene, and as such, birds cannot be bred to have a greater amount of it in that regard. They can, however, be bred to have higher quality feathering, which would allow the sheen to have greater visibility.
Diet and care also affect feather quality, cater to these two areas, and increase your poultry aesthetic. Feed that is corn-based or otherwise high in yellow xanthophylls can cause the green to turn more of a purple color. If feathers are worn or have seen an excessive amount of sunlight, they will lose their luster and appear brown. This is common close to molt and will be rectified when new feathers grow in.
White spots or patches also go hand in hand with extended black. It works much like gray hair does in people. As the bird ages, more white will appear. Some birds might show little to none, while others may turn almost completely white in their old age. Females tend to show a greater degree of this phenomenon than males do. Breeding and raising young will speed the process up — again, much like grey hair in people. It seems to be tied in with the green sheen in that birds who end up with large amounts of white in their old age had normally been particularly shiny when young. Although if showing your birds, the white is not acceptable, it is quite attractive in its own way. The way it appears is random and unique. It can make for easy identification of individuals from a distance.
Much research hasn’t been done on the correlation between plumage and skin color, but some observations seem to hold true in self-black breeds. The bills are darker but can be orange or yellow. It would seem that the commonly black bills of the Cayuga duck or East Indies are the result of selective breeding over many generations rather than tied to extended black itself. The same goes for foot/leg color. Although dusky patterned birds have slightly darker feet than wild patterned ones. This is another area in which diet plays a large role. The sex of the bird is another factor. Females use the same yellow xanthophylls found in coloring the skin to build yolks when laying. As such, less gets deposited in the bills and feet, causing them to be generally darker than the corresponding males. This is especially true while laying, which adds to the aesthetic of their nuptial plumage.
Self-black birds have a fairly simple genetic makeup when compared to more complex colors. Even with this being the case, there is no shortage of attention garnered at shows or in backyards by the birds that display this plumage. A solid dark background with a brilliant emerald sheen is a wonderful sight to behold. This is especially true when in contrast with lighter birds. In the past, it was one of the most popular plumage colors, only falling out of favor for lighter birds that leave a cleaner-looking carcass. In the present day, ducks are less likely to be raised for the table, and this has seen the popularity of self-black breeds grow. My hope in writing this article is that it will continue to increase, and more people who raise poultry will consider adding such beautifully colored birds to their flocks.
Originally published in the June/July 2021 issue of Backyard Poultry and regularly vetted for accuracy.