Or, mix something barred, ie, BR, Dominique, and whatever fudge the white legs, smudge the barring and call it a Cuckoo Marans. The real test is whether it will lay a nice dark egg. Very few do which lends little credibility that the birds sold were true. Popularity does this. I'd have no idea, but my gut says that the number of true Marans isn't anywhere near the number of birds sold as if they are. Shrug.
I agree. I added a couple of hatchery Cuckoo Marans to a chick order once on a whim, and I didn't get eggs that looked different from any other egg in my flock. Also, the hens were just plain stupid, and stood there looking at hawks after the rooster gave the alarm and all the other hens had taken cover. I lost three pullets that year to hawks, and every one of the three was a so-called Cuckoo Marans.