That's the only thing I can think of. My only guess is that they got it from hatchery stock, which sometimes mixes single combs with the rosecombs because rosecombs have lower fertility.
So still think she's a female? Brownie has a huge comb compared to her hatch mates, it's also more red then the others. Is she supposed to have a big floppy comb? What is the proper name for that type of comb.