Really it's too early to sex them - if you wait till 6-8 weeks you can post individual photos of them at "what breed or gender is this." It's very difficult picking out bits and pieces of different bodies among so many varied chicks in the photo.
Generally barred rocks can give you some clues. The males usually have thicker legs and are more a gray barring. Females are black barred. Hope this helps for now.
Glad you could join the flock! I too agree with drumstick that it's too early to tell the sex of your chicks. Defiantly post in the what breed/gender section when they are older. Good luck with them and your pic is lovely. Enjoy BYC and all the chicken chat
The barred rocks all look like pullets. BR pullets tend to be darker, have a round light spot on top of the head, and a dark stripe up the front of the legs. The cockerels are lighter in color, the spot on the head is irregular, and they lack the dark coloring on the front of the leg. With the other chicks, you will need to wait.
I agree with eggcessive.. It would be easier to tell if we could see the legs though.. I once read a thread that had some pics on here that showed the difference and it was very obvious with barred rocks.The male legs looked really light compared to the female legs.. I'd look for those pics.