We discussed doing some experimentation, me included, but don't think anyone ever did(me included :oops:).
I have some CL that lay abysmally pale blue eggs, not great for making Olive Eggers. Tho I guess you'd have to supplement diet forever to keep the blue bluer.
I'd guess most blue layer...
Have seen this come up more than a few times, can't remember any viable solution being proven. Not sure why feeding liver comes to mind, might be totally off base.