Join Date: Oct 2009
Location: Just south of sanity
How hot has it been where you live?
It's been in the middle 90s here, and my boys will hide out in their stalls until twilight. They have free run to go in and out, and I've noticed they'll stay in if given the chance.
It's not unusual for horses to have a mild colic when the weather changes so dramatically.
His not eating does concern me. Mine eat no matter what the weather.
You might want to give him hay and no grain until he perks back up. Hay and water are fine, especially if he's feeling a little icky.
Like people, they can get overheated. Does he have a fan? Many horses do well if left in their stalls with a fan blowing on them.