I was looking up pictures of cuckoo marans and mine looks more like a pullet to me. Even the pullets have large combs but the roos have a really big comb and it's bright red. My maran's comb is pink.
on cuckoo marans the spaceing and the darkness of the feathers is how you tell that marans are roo or pullets,roos feathers are farther apart and whiter than hens feathers.