"Mutts" or not they are about the most awsome chicken there is.
They were the for runners of the Ameraucana and Araucana breeds (the original imported stock anyway).
I have gotten EE's with gray (bluish), green, yellow, and white legs. I try to not breed the yellow and white legs on only green and blue-gray. Sometimes even taking care not to breed it on it sometimes will still pop out as will egg color.
I only hatch out blue and green eggs but sometimes the brown egg gene will still come through.