A Cornish Cross (Breeding?) Journey

[Ridgerunner]

But it has a single comb rather than a pea comb like his older sisters… and I hear the pea comb is linked to the blue egg gene

The way the pea gene is linked to the blue eggshell gene is that they are pretty close together on the chromosome. A genetics guru on here years ago said that the two genes are carried together about 93% of the time. That means he has a 7% chance of having the blue eggshell gene. Not great odds but don't give up hope.