It would help to have more information as to age and breed. If this chicken is approaching laying age, it is probably a pullet. The body looks more like a hen and the legs are not overly large. If it was a rooster, it would most likely be crowing by now.
At four months, I would vote pullet. At that age a RIR roo would be getting green tail feathers and body shape would be very different from this girl. Her comb and wattles indicate to me that she will be laying in a few weeks.
I vote pullet. I can't see the saddle and hackle feathers real well, but they look rounded, not pointed. The general body conformation looks like a pullet. The legs in the second photo look a bit heavy, but I think that is probably due to the angle of the shot. The wattles don't look quite as big as I would expect on a rooster that age. I'd be expecting eggs soon.