Then your best bet is to probably wait. There can be some things like speed of which the wing feathers grow in, that can help tell gender but they can be unreliable sometimes as well. You don't have to wait until they crow or lay am egg but unfeathered chicks is a little early unless you notice a really reddened comb
When you post pics again, try to have the bird standing and take pic from the side. This allows people to see the stance, and leg thickness. Get wattles and comb in that pic or in a separate pic. Wattle and comb development can really help with ID when they are younger than 12 weeks. Male saddle feathers show up around 12 weeks, so before that, we need to see the other elements of the chicken!