Blue Egg

The blue egg gene is an incomplete dominant gene in chickens that causes the bird to lay a beautiful blue colored egg. This is caused from an increase of Biliverdin deposited onto the egg in the shell gland (4).

With one copy of the gene, the egg with be a paler blue then the brilliant robin's egg color often seen with homozygous (two copies) of the gene (1). Blue egg can also be mixed with the brown egg gene to create green eggs in various shades (6). Birds will typically lay the most vibrant egg colors at the beginning of each reproductive cycle and lighten up as the season goes on.

Blue and green eggs in any shade do not have any impact on the overall nutritional value, egg size, egg shape, bird health, or general plumage traits (2)(7), however the blue egg gene can cause the bird to lay less eggs overall (2).

The trait is most often seen in Ameraucanas and Araucanas, the only two recognized APA breeds to lay blue eggs (10), but can be bred into any breed. It is also a trait bred for in hatchery Americanas (Ameraucana crossbreds), Easter Eggers, Olive Eggers, Crested Cream Legbars, and Isrudds.

Breeding with the Blue Egg Gene:

For more information about breeding with this kind of gene, including tips and tricks and a full explanation of how these results were calculated, please see here.

Blue Egger x Blue Egger = Blue Egger

Blue Egger x White Egger = Light Blue Egger

Blue Egger x Light Blue Egger = 50% Blue Egger, 50% Light Blue Egger

Light Blue Egger x Light Blue Egger = 25% Blue Egger, 50% Light Blue Egger, 25% White Egger

Light Blue Egger x White Egger = 50% Light Blue Egger, 50% White Egger

Blue Egger x Brown Egger = 100% Light Green Egger

Blue Egger x Light Green Egger = 25% Light Blue Egger, 25% Blue Egger, 25% Light Green Egger, 25% Dark Green Egger

Dark Green Egger x Dark Green Egger = 100% Dark Green Egger

Note: It is impossible to tell by looking at a rooster whether they carry the blue or brown egg gene. This is why the blue egg gene is often bred with an incomplete dominant trait, such as beards/muffs, or certain plumage patterns, to keep track of the genes across both sexes.

There is no correlation between the muffs commonly seen in Ameraucanas and Easter Eggers and the actual blue egg gene.

It is also worth noting that the darker egg layers will typically lay less eggs than the lighter egg layers. The darker and more pigmented the egg, the less overall eggs a hen tends to lay.