So just today I picked up 15 Blue Copper Maran hatching eggs, and the breeder and I talked for a while. She told me she feeds her Marans a certain food that darken's the color of the eggshells, but she said she wouldn't give away her secret, and encouraged me to find it on my own. She also hinted it's region-specific, and she's from north-western PA. On my way up I saw a lot of sweet corn and beans, so maybe one of those?
I'm kinda thinking she's full of it, because I've never heard of egg shells changing due to diet, but please correct me if I'm wrong
Anyone who might know what it is, don't hesitate to comment. And yes, I am cheating through the power of the Internet.
you are right. diet does not affect egg shell colour (unless it can affect genes responsible for the egg shell colour which sounds impossible).