Pullets or Roos?

[RhondaC]

I have 3 Buff Orpington and 3 Silver Laced Wyandotte chicks. They are about 3 weeks old. Can anyone tell at this time which are hens and which are roos? I was told the 3 buff were sexed as hens when I got them but not sure.

 

[Johnny17]

I think that only the first is pullet, and maybe the bird at 4 picture.