If they are 4wks now, it is pretty easy with that breed to tell the sex. The male with have the really nice barring. The females are a duller and lacking in the barring. If you can post pics, we should be able to help you.
Here are mine at 6wks. They are two roos (the ones with the sharp barring) and three pullets ( the darker ones).
Thank you very much for the quick reply.....I just wet back out to my chicken coop and was able to clearly see that I have 3 males and 3 females. I have had bad experiences with Roosters. Are the Barred Rock males aggressive? Is there a better way than other to make them friendly or is it just dependent upon each bird?