#1, #2, and #4 are looking like cockerels (though #4 might be a pullet). #3 looks like a pullet.
It has a rather large comb for its age (though, the comb isn't red yet).What makes you think maybe cockerel for #4? Just so I know what to look for. Our mailman thought it might be a boy too. It's the oldest chick of the 4 by a few days. I really hope it's not because we are especially attached to that chick.