appearance at almost 4 weeks

Good morning, everyone.

I have a quick question: How would you describe the look of your RIR chicks at about 4 weeks old? Mine have at least doubled their size and they appear to be healthy and they also act that way. However, I don't think their feathers look really great. Most of the fuzz is gone, but the feathers that they do have are not "smooth". They just look overall "skimpish and unhealthy". Is this because of the stage that they are at? My BR's have much nicer looking feathers - much smoother and shinier. I just want to make sure that my little ladies are healthy. Like I said, they act very healthy. Whenever I go to feed them, they go crazy, running around and jumping up, trying to fly out of the brooder, chirping and squawking and making a fuss. Some of them are very selfish, wanting to have my hand full of feed all to themselves! What a trip!