https://www.backyardchickens.com/threads/how-does-my-mama-heating-pad-look.1578429/
Here is one. Just search "mama pad" and you'll see quite a few ideas.
Shoot. I am sorry she is in such bad shape. I think your idea of a brooder plate makes sense, considering it looks like she is drying out. My apologies for being so harsh about my criticism. Before they really took off, the plates were a decent quality. Now, like everything else they are being...
They fail, overheat, aren't adjusted properly, etc.
There are a lot of variables with a brooder plate that just aren't there with a traditional heat lamp.
A good brooder plate is one that you throw in the garbage.
I know there are folks who really love these things, but I would wager you can attribute more chick deaths to them than any other piece of brooding equipment.
I am bias (obviously) but your chick may also have trouble learning and...