Hi, I have a small flock of Opal Legbars. I purchased hatching eggs two years ago that were all blue/blue green. From those birds I have hatched more for myself that all came from blue/blue green eggs. I have now found two tan eggs in their boxes. They are separate with no other birds having access to their space. Where is the tan egg coming from with all parent stock coming from and laying blue eggs? I need help with the egg color genes on this one! Thank you to any info you guys have!!
The blue eggshell gene is dominant. That means a hen can have one copy of that gene, and one copy of the gene for not-blue eggshell, and she will still lay blue or green eggs. Males don't lay eggs, but they still inherit the eggshell color genes from their parents and pass them on to their chicks.
If a pullet inherits not-blue-eggshell from the mother and from the father, she will lay not-blue eggs (brown, tan, cream, or white).
You can get genetic testing to see which of your birds have two copies of the blue eggshell gene (good), which have one copy (not good), and which have no copies.
If you're in the USA, this place can do the testing:
https://orders.iqbirdtesting.com/order-bird-dna-test/
If you don't want to pay for dna testing, or cannot get it, you can also use test-mating.
To test mate, breed a chicken with one who does NOT have the blue eggshell gene, raise several daughters, and see if any of those daughters lay not-blue eggs. If any daughter lays not-blue eggs, then the bird being tested has at least one copy of the not-blue shell gene. If you raise quite a few daughters and they all lay blue or green eggs, then the bird being tested probably has two copies of the blue eggshell gene (because every daughter got one.)
DNA testing is much faster and cheaper than test-mating, because you don't need the time, space, and feed to raise a bunch of daughters to laying age just to check their egg color.
