Well... here's what I see. The tail is not long and arching, which indicates hen. There are no distinct saddle feathers which indicates hen. The coloring to me looks like a roo, as the barring is more white than black, which is indicative of a roo. For the coloring, the best way to tell this is to look at the your BR hens and this one side by side as this is the best way to see the color difference. The comb and wattle look like a roo but the lack of long growth behind the ears indicate hen. Others have said hen.... so go with hen. If she/he doesn't start crowing and lays an egg, she's a hen! If she starts crowing (like a real crow, some hens try to crow but not very well) and never lays an egg, he's a roo.
My BR hens (I have 3) and my roo look so different and act different, it's just obvious. For me, yours is harder to figure out. Great luck, I hope it's a hen!
Guppy