HELP! Yellowing skin.

[Calicoes]

Please help. I’ve never seen something like this with my other chickens. The skin around her butt is yellowing. Is this mange? Her vent is open and her poop is normal - she’s eating and drinking fine. The skin feels dry too. Other chicks skin seems fine.

 

[Calicoes]

The rest of her skin looks pink there are some small yellow crust pieces though and she does seem to have some feather loss.