Heather, I'm so glad you kept this post alive. If you recall, I bought 6 "Barred Rock Pullets" and was suspicious of 4. (I've since determined that I was sold 2 BR pullets and 4 male black sex-links.)
The coloring of mine was darker than yours so I was really hoping they were just pullets with really developed combs. I heard one baby crow a few weeks back and then nothing so I thought that might be the kids playing (they do that sometimes).
Yesterday morning, we heard definite crowing from the coop. And a lot of it!! We live in the suburbs and can't have that. So my husband and I chose two that we think were the most likely culprits. We slaughtered them and butchered them yesterday. I had never done it or seen it done before. Now, we'll have chicken soup for dinner. (it's OT and graphic so I won't post details on this thread, but if you have questions, send me a PM).
Anyway, no crowing this morning so the other 2 cockerels have some reprieve, at least until they too start crowing like crazy at 5am.
Heather - I forgot, did your birds have some blue feathers mixed in too?