Willawong Hill
Songster
I think what you have to do is cross the blue egg layer with a white egg layer. If all pullet offspring lay blue eggs then your blue egg layer is probably homozygous; however, if even one pullet lays white eggs then your blue egg layer is heterozygous. Problem is you end up with a lot of pullets you know are heterozygous then so only useful to try if you have time and space.So that was what I was asking, was how can you tell that either parent carries two copies of the blue egg gene? I’m not sure that you can