Good description. For the first couple of weeks, it can be a bit difficult to tell the Barred Rock and the Cuckoo Marans chicks apart, but it doesn't take long for the difference to be noticed. The more yellow legs on the Barred Rocks is what I used first. As they feather out, the difference is definite.The color of their legs are different, as are the beaks; yellow for Rocks, white for Marans. And Cuckoo Marans are quite a bit darker than Barred Rocks, and their barring isn't nearly as crisp. The differences are subtle, but you will eventually be able to spot them.