They all have saddle feathers, but hens will have rounded saddle feathers and roosters will have pointy saddle feathers. I can't really see from the pic, so just look at him/her and check if the are pointy or rounded. Good luck!
Rooster, for sure. The color tells you just after hatch, usually. That more questionable one is a rooster, no doubt, too, however, his legs are the wrong color for a Barred Rock.