By 6 weeks, males should have a prominent red comb and definite wattles, along with the sturdy legs that indicate a heavier bird, generally male. I can pretty much pick out my boys from the hatch three weeks ago. Pullets will have pale, almost white or yellowish combs, and small wattles at 6 weeks, but if at 6 weeks they could also be a very pale pink. Their faces may have started flushing, getting red then fading back to the white flesh color. Their legs and necks will look slightly more slender.
I loved my Naked Necks from day one, they are such sweet birds; but now the summer heat they are really wonderful. I am not nearly as worried about them dieing from the heat, we have been over 100 most of June, and the hot part of summer is just starting. They enjoy the wading pool, even being gently spritzed with the hose when the heat is bad, like this afternoon 108 is the forecast high.