A little of the confusion comes in because there are more than one gene that control brown egg coloring, in fact there are 12.
Blue egg is a dominant gene meaning that the bird will lay blue eggs with onyl one of the blue egg genes, So if one of the parents is Homozygous(having 2 blue egg genes) meaning that they come from a long line of blue egg layers that breed true, then all of the f1s will lay blue eggs or carry 1 of the genes.
However if there are brown egg genes in one of the parents the brown will be deposited on top of the blue causing any number of shades of green.
So your best bet for a blue egg cross is with a white egg layer, and then you have to keep careful records and make sure to mate the F1s to more blue egg layers because they only have one gene and so if they are mated to birds with out the blue gene they will only produce 25% blue egg layers. Once you get your line homozygous they will breed true.
Araucanas, although the standard calls for a blue egg will lay a varying degree of colors possibly because they have brown egg layers in their lines. The Araucana was originally made as a cross between the Colloncas(rumpless blue egger) and the Quetero(tufted brown egger)
Blue egg is a dominant gene meaning that the bird will lay blue eggs with onyl one of the blue egg genes, So if one of the parents is Homozygous(having 2 blue egg genes) meaning that they come from a long line of blue egg layers that breed true, then all of the f1s will lay blue eggs or carry 1 of the genes.
However if there are brown egg genes in one of the parents the brown will be deposited on top of the blue causing any number of shades of green.
So your best bet for a blue egg cross is with a white egg layer, and then you have to keep careful records and make sure to mate the F1s to more blue egg layers because they only have one gene and so if they are mated to birds with out the blue gene they will only produce 25% blue egg layers. Once you get your line homozygous they will breed true.
Araucanas, although the standard calls for a blue egg will lay a varying degree of colors possibly because they have brown egg layers in their lines. The Araucana was originally made as a cross between the Colloncas(rumpless blue egger) and the Quetero(tufted brown egger)