Unfortunately I can't help you because I am a newbie to the chicken world!! But I was hoping you could maybe you could help me out a little? The chick in question, what breed is that? My chicks are about the same age but we bought them at Atwoods(like tractor supply) so we don't know what they are. We only have 2 chicks, from the same bin of bantams. Well my daughters chick is probably a bantam (unknown breed) but the other is now HUGE and looks like the median brown you have identically!!! If I were to guess you have a pullet because its such a match and ours had a pink band on its wing that I removed. But still not sure. I think I know more about chickens than the folks at Atwoods do.