Minecraft 18w43b, Minecraft 18w43c
I noticed that when you put any type of horse armor on any tamed horse (I have not checked untamed yet) the horse texture disappears and becomes air.
I personally find this funny because it could be used as an way to disappear and move throughout an players base when you want to mess with him.
Although it would be cool to have armor that makes the horse invisible or an enchantment for the horse armor to make it go invisible I still think this glitch should be fixed.
Here is a picture to show you both the horse going invisible and showing what its equipped with:
MC-137563 Horses become invisible when equipped with horse armor