Araucanas

by
Rosalyn Upson

Araucana Club of America


Drawing by Cathy Brunson

The Araucana is a challenging breed that combines the unusual traits of tufts, blue eggs and rumplessness. Tufts are unique to Araucanas, and each is composed of a group of feathers that grow from a protruding flap of skin located near the ear, called a peduncle. The mutation that causes this abnormal flap is an autosomal (not sex-linked) dominant gene represented by the symbol Et (extended tuft). This gene is completely different from the one responsible for producing the muffs and beards seen in other breeds, such as the Ameraucana. The tufts gene is lethal when present on both chromosomes (homozygous), and the chicks die in-shell and don't hatch. This means that a flock will always be a mixture of tufted and clean-faced birds. There is wide variability in the size and shape of tufts. Unfortunately, many birds may have uneven, small, or only one-sided tufts. But a bird with large showy tufts makes an unforgettable impression!

It is often asked whether it is better to mate tufted to tufted or tufted to clean-faced birds. According to classic genetics, crossing tufted with clean-faced will give you 50% tufted and 50% clean-faced, with none dead in-shell. This cross will give you the greatest number of live chicks. If your goal is to produce the largest percentage of tufted birds and minimize the percentage of undesired clean-faced chicks, then tufted to tufted matings are best. In this case, 50% will still be tufted, 25% will be clean-faced, and 25% will die in-shell because they have two copies of the tufts gene. So the percentage of birds that hatch will be 75% tufted and 25% clean-faced. In both cases, you will get the same number of tufted chicks.

Araucanas are rumpless, which means that they do not have a tail, any remnant of a tail, or even an oil gland. This trait is caused by an autosomal dominant, non-lethal gene. Even though the gene is non-lethal, it can have an affect on fertility because the lack of movable tails can create difficulty in maintaining the physical contact necessary for fertilization. Some breeders trim the fluff around the vent to aid physical contact. But other breeders have found that if they don't trim and let nature take its course, over time the fertility will increase. Other breeders make the mistake of mating a rumpless bird to a tailed bird in an effort to enhance fertility. If the rumpless bird is herterozygous (one copy of the rumpless gene), the resultant chicks will be 50% rumpless and 50% tailed. However, many of these rumpless chicks will only be partly rumpless with a few tail feathers at odd angles, creating an ugly bird. This is because rumpless modifier genes exist, and breeding to a tailed bird introduces these genes into the offspring. By breeding only homozygous rumpless to homozygous rumpless, over time these modifier genes get eliminated.

Araucanas are noted for laying a blue egg. The blue color comes from an autosomal dominant gene that has been given the genetic symbol of O. This blue color is caused by the deposition of a liver bile pigment throughout the egg and can be seen on the inside of the eggshell. The pigment is concentrated in the egg-laying apparatus and deposited at the same time the as the calcium carbonate that makes up the egg shell. In contrast, the color for brown eggs is deposited by the shell gland as a thin layer on the outside of the egg shell just before laying. If you break open a brown egg, it will be white on the inside, while a blue egg is blue throughout.

If you cross a blue egg-laying bird with a brown, the shell will be blue but have a brown coating over the egg surface. At least 13 genes that affect the color for brown eggs have been identified. Just think of all the shades and tints of brown eggs you have seen. So depending on the overlaying shade of brown, the resultant egg might appear as varying shades of green, olive or pink. Unfortunately, it is relatively common to find Araucanas that don't lay a pure blue egg, and are "contaminated" with brown shell genes. If this is the case with your Araucanas, use birds for breeding that hatch from the bluest eggs, and you will make progress. If you are fortunate enough to obtain some hens that lay pure blue eggs, be very careful not to breed them to birds that have mixed-color eggs.


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