Footwear problem- hot climate + horses?

okaay so i'm away to spain on sunday to volunteer at a horse rescue charity and i need to know what to wear!! it's over 30 degrees C so i have to wear shorts, but seeing as i'll be around horses, i'll need suitable footwear. I'll need something that is sturdy and won't make my feet overheat. I also could use something stylish, if available. Oh, and I'll need to be able to get it from a shop in the UK. thank you so much :)