Blue egg gene
The blue egg gene is associated with blue eggshell pigment. Blue, green, and teal shell pigments can hide inside ordinary looking hens and roosters.
- The blue egg gene (O)
- Blue colours the whole shell, inside and out. It is dominant, so one copy (O/o) is enough for a hen to lay blue-shelled eggs.
- Blue + brown = green or olive
- Brown is a coating laid over the outside of the shell. A hen with the blue gene from a brown-egg line lays green or olive eggs, and a heavy brown coat can make a blue egg look brown.
- Check inside the shell
- Crack an egg and look at the inside of the shell. Blue or green inside means she has the blue egg gene, even when the outside looks brown. White or cream inside means no blue.
- Why brown isn't in the odds
- Brown shell colour comes from many genes working together, so no single DNA test can predict it. This calculator shows the blue part.
- Roosters
- Roosters never lay, but they pass the blue egg gene to their daughters. Testing is the only way to know what a rooster carries.
How your results are written
- O/O
- Homozygous blue — equals two copies of Blue Egg Gene
- O/o
- Heterozygous carrier of blue — equals one copy of blue egg gene
- o/o
- Non blue layer — no copies of the blue egg gene