Roo or hen or too soon to tell?

[Makiks]

Hi all! Can anyone tell if this is a too or hen? The chicks are three weeks old. Just curious because of the visible comb. New chicken owner here with not much experience. Is it too soon to tell?

 

[HappyClucker7]

Pullet

 

[4Urbanchix]

I’m not sure about the other one but the barred rock looks like a pullet because of the darker barring