I've been trying to think of a way I can prop her butt up so when she goes she doesn't have to sit in it. Since she can't move to get away from it. It doesn't stick to her skin but I will definitely do the Vaseline so she doesn't get poo burn from sitting in it during the night.
Another thing , I use oaten chaff in the brooder instead of wood chip or sawdust. If you lined the bottom of her pen with it , say 3-4 inches deep it may help with pressure and the poop . I don't know where you are , but a 25 k bag of chaff is about $25 here and it's easy on your garden. Unlike sawdust. Plus I found that the chooks would eat the shavings.