thank you all for your replies...
we ended up getting a 3rd barred rock from the same place (so the same age). so, if "Peck" is a roo, then we have to give him up (county ordinance), but we still have 4 hens. If "Peck" is a girl, we are lucky and have five hens!!!! I'll let you know if "Peck"...
so... it seem like half of the guesses are roo and half are pullet.... thank you all so far for your guesses. time will tell! she/he will be 3 weeks on thursday. when does the comb usually turn red? or what are other signs I can look for? thank you for your help. we are new to chickens...