Townline Hatchery has a couple different lines of OE. On their website description they claim some are Cuckoo Marans malex"Americana" and others are "Americana"xBlack Copper Marans. Also, their picture for OE is not even one of their own stock. Townline "Americanas" would definitely be considered Easter Eggers (non-standard colors, any color eggs, may have muffs.)I feel like I’m ignorant here, but isn’t an olive egger just a blue layer crossed with a dark brown layer? The hatchery could have crossed easter eggers, which are themselves kind of a mutt, with welsummers or marans or something, and with the genetics lottery, you get a mishmash of traits for each bird? (which would explain how they’re all kind of different)
I could see the partridge or wild-type from their "Americanas" giving the OE the black vs. brown (m vs f) breast look.