Celadon

Celadon is a gene in coturnix quail that causes the hens to lay light blue eggs (1). The egg can be any shade of blue, from a very pale, almost white color to a vibrant robin's egg blue and even some light shades of green. Eggs may be a solid color or speckled with brown (2). It was originally discovered in 1993 in a Japanese lab, and named "celadon" after a Chinese porcelain color that was popular (7).

It is completely separate from plumage genes--the celadon gene can be bred into any color or size of coturnix quail, and the color of the egg does not change the color of the feather. Because it is completely separate from any plumage or structural mutation, there is no physical way to tell if a bird is celadon unless they lay blue eggs, and there is no way to tell if a rooster carries the celadon gene outside of test breeding.

The celadon gene also does not "develop", the bird will either lay blue eggs for its whole life or not at all. The color of blue may change throughout the hen's life, typically starting more vibrant and then fading as the bird gets older, but it will still remain some shade of blue and never lay the standard brown speckled tan egg (4).

It also is entirely recessive, meaning there are no signs if a bird carries the gene (1). The idea that carriers of the celadon gene lay eggs with a blue insider is a myth-- almost all healthy coturnix quail will have blue inner shells (5). The only way to tell if a bird carries one copy of celadon is to test breed and keep strong records. It is advised to keep birds in individual cages while test breeding until the bird is proven to carry or not carry the gene.

There also was controversy between backyard breeders over whether or not the celadon gene was linked to a calcium or other nutrient deficiency, but this was never proven and a study found no correlation between egg and other qualities and the eggshell color (3).

Breeding With Celadon:

Note: because males do not lay eggs, it is not possible to tell if a male carries one, two, or no copies of the celadon gene without individual testing of the female offspring.

Celadon x Celadon = 100% Celadon

Celadon x Standard = 100% Celadon Carriers

Celadon x Carrier = 50% Carrier, 50% Celadon

Carrier x Carrier = 25% Celadon, 50% Carrier, 25% standard

Carrier x Standard = 50% Carrier, 50% Standard