Male specific saddle feathers don't usually begin to develop until about 10 weeks old, and can take several more weeks to be clearly visible. Your chick is just starting to feather in on the back and looks completely normal.
There is no sexlinking with that particular cross, if that's what you are asking. You have to wait and see. Neither are obviously male, yet. Anytime you are crossing breeds, there is a possibility for a huge range in looks from chick to chick.
For example, most of these chicks have the same...
Your barred birds are not pure Barred Rocks, they are definitely mixed, and they all look male, even the one you can just see the tail of.
Your reds all look like pullets with their broad, rounded back feathers.
Still really blurry, but I think I can make out male saddle feathers on at least two of the Rocks. They are the long, thin feathers on the backs that only males get.
Not really. Most black feathering will have a greenish tint when the sun hits it just right. I've got 5 solid black girls in my flock, and all of them have a green or purple sheen to their feathers. One of my Barred Rock girls is green when the sun hits her black bars just right.
Most roosters...