I had a horse with a decent jump (could clear three blocks) wearing diamond armour. I was on with my son and he used it for a while, but forgot to put it back in the stable. We have no idea where it wandered off to. If you see a horse with diamond horse armour and a saddle wandering around, could you bring it back to spawn and put it in the horse corral?
They must de-spawn after a while, I had a horse too, tethered outside my base and it just vanished one day, who knows where it went
Sometimes tethers will glitch out, and horses will just wander off.
I've had tethered horses disappear, with the tethers floating on the ground where they were tied up. Since then, I've always corralled my horses with at least a two block high fence. The problem with this one was my son not putting it back in the corral.
I'm not sure that the horses despawn, though. There are wild horses that I saw in the first month if the new server that I still see in roughly the same area now. I captured a couple more, but I'm down to one saddle and I've lost that diamond horse armour.
Well if anyone finds a dark brown horse with a saddle wandering around it may be mine ;)
but I doubt it, probably fell down a hole or walked into lava or something... OR is having HORSE ADVENTURES on the map!