MartinFarm, you didn't get barred rocks. You would of seen barring in the 1st week. Start you a new thread with pictures of your birds. Someone will help you figure out what you got.
Black Sex Links
Jersey Giants
Australorps
Are a few possibillities.
Both male and female barred rocks have a white spot on top of their heads. Yes it could be a black sex link. Black sex links only the males have the white spot on the top of their heads.