Yes. The penciling changes.
If you look at the girl in the background, you can see her chest feathers. The chest feathers show the penciling first, then the rest of the feathers follow.
It's a girl. Look at my old roo's comb at 8 weeks. Sorry the photo is so dark, it's hard to see coloring.
and here he is at 12 weeks old.
This is Maxine (pullet) at 9 weeks old.