Looks like a New Hampshire hen, actually...I have the male version of that breed and he looks quite a bit different!
But check its saddle and hackle feathers (which are not clearly visible in this photo). If it's a roo, they will be long, thin and obviously pointed. If they're rounded like the saddle/hackles in the chicken in the foreground of this pic, then 99% chance it's a hen (until it lays...then 100% chance