Mangy Looking Baby Chicks. Lice? Mites? Help Please!

[scooter8]

Hello, recently purchased one week old black copper marans and one 2 week old black copper marans. Recently, I have noticed that they have become quite mangy looking. They are loosing some feathers and the feather they do have, have quite a grainy texture to them. Is this normal? The older one is now about 4 weeks and the younger one is around 3. The younger one isn't looking as bad, but it's not in as good condition as when I got them. When do baby chicks start getting adult feathers? I just really hope it's not lice or mites, and I'm fairly sure it's not because I checked and I cannot see any eggs or movement at the base of the feather. I am housing them in a cage, in a large coop with all my older 12-14 week chickens.
Hope I can get some answers. Take a look at the pictures I attatched.
Thanks.

 

[farnorth]

they look normal to me. they go through a stage while feathering out where they look pretty rough.

 

[Brie6895]

This is complete normal they're just getting their feathers in
That one looks Like it may be a rooster. Most of them will feather in slowly which might be why it is worse than the younger one.