Very neat! If all the dark/black chicks have the spot on the head it's likely they're all Barred Rocks.
Here's a Black Australorp at 2 days old:
Also 2 days old, BA is in the back, Barred Rock is in the front.
I believe your #6's are Barred Rocks-- black with the white spot on its head and the wing edges. The black one with a white chest in the 2nd pic is a Black Australorp. You'll know when the wings start to go stripey.
2 days:
17 days: