I have Buff Orpingtons and Black Copper Marans that are currently 17 1/2 weeks old. I have two of my flock that I believe may be roosters - one of each breed. Here are some pictures of each. I don't have any experience with them at this age, so please let me know what you think they are and what specific characteristics make you think that. From what I've read and can see - this Buff has a comb and waddles that are more red and developed than the other. The Maran's don't necessarily seem more red, but do seem more developed. I've heard you can tell from the feathers as well, but I don't know what I'm looking for.