so I have 8 chicks..this is my only cuckoo marans.. She is 3 weeks old..amazing how fast they grow.. hoping she is a she..is it too early to tell yet? She's probably the most skittish of the girls I got.. the others are RIR's, SLW, Plymouth Barred Rock, and a Wellsummer..
That comb looks a bit suspect to me. If it is a boy you should start seeing the comb redden and some reddish wattles showing up - soon. Compare it to your other chicks that age and see if the comb seems more developed. I have some 3 weeks old Black Copper Marans that are obviously boys, so there is some hope that yours is a girl.