Shoot, those Plymouth Rock hens can have combs that put the roosters of other breeds to shame. Their 8 weeks along you say?
Well, considering you hear crowing (and 8wks is just about the time a lot of folks seem to start hearing their roos announce themselves) and their combs are more developed at this age than older chicks of the same breed....
Adds up to roos to me, but I'll defer to those with experience in the breed.
mm I thought with barred rocks you pretty much could go by whether they are mostly white or mostly black. Which is which is something I don't know though. Hopefully someone that does can pipe up.
That looks like a hen to me. BR roos have alot more white and the black is a lighter color, and the hens are more black with a little bit of white. Also, you said he is 12-15 weeks, my 9 week old BR roo has a comb the same size, if not bigger, and has alot more white on him. You can also tell if he is a roo or hen by the way he acts. I knew mine was a roo before any real physical features showed up because he was always the first to get anything and he always came after me when I went to feed or water them.