They could be 10 weeks or so -- They are definitely all pullets. Here are some of mine at 9 weeks. You can use the fence and the red, standard width bricks for size reference (the smaller ones are bantams - the black ones are Marans and except for an EE roo are the largest of the bunch).
This is my Red Star a week later - at 10 weeks:

This is my Red Star a week later - at 10 weeks:
