Olive Egger isn't a breed, its a type that is characterized by laying olive green eggs. If it is an olive egger, than as said above, many different breeds can go into the making of them.
Olive Eggers are typically made from crossing cream legbar, easter egger or ameraucana to welsummer or marans. So the looks can be quite varied, though black is a common OE color.I guess I should be asking... do they look like any certain breed? I mentioned olive egger because after we picked them out the man we bought them from mentioned they may be olive eggers.