First, a horses normal temperature is about 101 degrees so he didn't have much of a fever at 103. Second, if you know your horse gets stocked up when he doesn't get out of his stall why didn't you put on a raincoat and get him out? What part of him will melt in the rain? If a horse is eating and drinking it isn't usually very sick either. I don't see what was so very wrong about what the BO did. She may have been doing other things and saw that your horse was acting okay and didn't want to take his temperature again. He was not about to die or anything.
There's nothing like the Rockies in the springtime... Nothing like the freedom in the air... And there ain't nothing better than draggin calves to the fire and there's nothing like the smell of burning hair. -Brenn Hill