We are fortunate that, under current conditions, our horses generally keep their masks on, except when they don’t. 🙂 However, at the previous boarding facility, my Rocky horse lived with the gelding herd. They played “fly mask gotcha.” Masks stayed on a few hours. Then play time.
I would frequently find the offending mask stuffed into a ground squirrel hole where it had been dragged as a squirrel trophy.