3 and 4 look like boys to me.
The genders look very similar for a LONG time and the only way at that age I knew who my boys were was by picking them up and looking through their wing/shoulder feathers. the first sign you have a boy will be dark red shiny feathers growing at the wing base. It can take quite a while for them to emerge and be visible. Their combs develope slowly, most of the roos are pretty docile, and the saddle and hackle feathers look very similar on pullets and cockerals. BLRW are tough!