My extremely old (probably ~40yo) mini horse died last night. I had actually scheduled his euthanasia with a vet, but he had his own ideas about the timing. He found a very comfortable spot in the barn, laid down on some hay, and passed peacefully.
He lived in a petting zoo for many years. I only owned him for 2 years, but he enjoyed slowly wandering around my farm, enthusiastically accepting senior horse kibble whenever offered, and always accepted hugs.