6 week RIR comb turning black

[ChickNik01]

I noticed my almost 6 week Rhode Island Red's comb was getting a little dark and doesn't seem to get lighter. This is my first time with chicks. Is she ok? I have one other RIR male and his is just fine

 

[nuthatched]

It could be sunburn, and that one might be a male as well. :/

 

[ChickNik01]

It could be sunburn, and that one might be a male as well. :/

Double bad news. Is there anything I can do about the sunburn? Right now they're in a sunny area, except while they get to free range

 

[nuthatched]

Double bad news. Is there anything I can do about the sunburn? Right now they're in a sunny area, except while they get to free range

Maybe some aloe? I know there's sunblock for animals but I don't know what if you can use it on chickens.