My horses keep disappearing.

First, my horse randomly disappeared. It was fenced in and had a lead equipped. It also had diamond armor. I was mining then when I came back up to the surface, my horse was gone. I could still see the lead connected to the fence. I searched for about 3-5 in game days. I luckily still had another pair of diamond horse armor and a saddle. I was exploring with me new horse when my game unexpectedly crashes (I am using iPad 6th gen) I re-load into the game and my horse was gone. It also had a saddle and diamond horse armor. Please fix this, super frustrating.