I know it's still pretty young to tell but maybe someone has a trained eye? I'm thinking its a cockerel based on coloring and markings.
At this age of bird basically you need to compare him or her to the others a bit. Are his feet a bit bigger than the others? The tail feathers a bit behind or smaller than the others? Even these aren't real reliable ways to tell at this point. At about 5 to 6 weeks you'll see a pinking of the comb possibly vs. the hens will have peach colored comb. I've never had an EE cockerel to compare feathering patterns with...but if this bird was sexed hen when you purchased I would say that's what you have. I just looked at the white tips on those back feathers, and those tails feathers look to be progressing nicely as a pullet would normally do.
