I guess I have to email myself the photos so I can post. Can't add pictures from the iPad. Darn it!
IF you got your chicks from a hatchery, it may be almost impossible to tell them apart. Hatchery Cuckoos can be clean legged and yellow legs too. Might have to wait till they lay eggs.... but then again the cuckoos are not known to lay a dark egg. Might always be just a guess. The barring on BR is not as good and heritage birds so it can look cuckoo too.
I learned early to NOT hatch my Cuckoos and BR at the same time..... same with Olive Eggers and Marans, they can look the same too.