Mmm not as easy as I thoughtSilkied feathering is recessive. First cross would have normal feathers and carry 1 copy of the silkied feathers. Crossed to a silkie you'd get about half the chicks with silkied feathers and half would have blue eggs. Blue egg gene is dominant so one copy and you'll get blue eggs.
Ive been working on it for many years. I used wheaten ameraucana so started with known hens with two blue egg genes. I Havent had a good male from a blue egg yet. So my hens only carry 1 copy of the gene at best. The 5th gen look like the rest of my silkies now so they are all leg banded. Here's hoping for a good rooster this year. Then I can work to getting two copies of the blue egg gene.
