

I am assuming you’re in the USA, go grab a 50lb block of sulfur/salt (it’s the yellow one) and some free choice minerals from the coop if you have one nearby. If not TSC works as well it’ll be more expensive though.
If you’re not in the USA, dunno where you can get those things, but they’ll help her keep water in.
Grab her a UV rated flymask as well. Because she is gray, she has a greater risk of skin melonomas. Also sun screen on her nose, but the UV fly mask will help a ton.
https://ceh.vetmed.ucdavis.edu/health-topics/melanoma-horses