I know the darker ones are girls and the lighter ones are boys but does it work the same if you cross a CM rooster with a BO hen? Our chicks are here and there are 4 dark ones and 1 light one but they all have more yellow on them than the purebred marans chicks did. I'm thinking 4 girls and 1 boy? We never have that good of a ratio. We always get more boys than girls. lol