He sourced some chilean stock that were pretty much mongrels.. cream Legbars get their blue eggshell gene from themOne of those really interesting things to read about is that Punnett - meaning the guy who showed how to use "Punnett" squares - worked with blue egg layers. I had a lot of fun a few years ago reading where he documented that blue egg is a dominant trait and the steps he took to develop true breeding blue egg layers.
The chinese version of the blue eggshell is allelic to the chilean Oocyan mutation so you cant combine both gene to get a deeper blue color.
We can confirm the sex linked nature of some brown egg shell genes with the user gide of some production type strain where Brown egg males mated to white leghorn type females produce darker shade eggs than the reciprocal cross