They will set rocks if you let them, but most of mine lay there eggs in the barn so I get to collect them up before they get a chance to start setting.
Chris
I'll put my vote in for Gamefowl American Game one of if not the best forager you will ever have.
I get from 5 to 6 eggs per hen a week and they free range truly free range and get about a 1/4 cup of feed per hen a day.
Chris