My vote is for the sex linked males. It's highly unlikely that you're going to pick up Marans at an auction in those kind of numbers for ???? well, I don't know what you paid for them I guess. Maybe if you paid enough that might make a difference. If the bid went up to around ummmmm.......it would have to be no less than $3 or $4 a piece. Most of the time they go for more, but at an auction I guess you're expecting a deal. Cuckoos don't bring as much as Black Coppers and the others, so it may be remotely possible, but I don't see any other coloring on them that suggests Cuckoo Marans. They look solid black, other than that spot on the top of the head. Plus, if they were Marans, the auctioneer would most likely have made a big deal of that fact.