I have a problem with tamed named mobs despawning when ever I unload a chunk I have lost two very good horses to this.

I have a problem that my named tamed mods disappear It is not to much of a problem when it is a sheep from my pen, but when it is one of my horses it get mad. Sometimes they disappear as I am riding them and the game crashes or sometimes a come home to see my horse gone. I have them name and tamed and when they disappear it makes me mad because I wasted a name tag also I only keep the best horses I can find. I believe the problem lies in the loading and in unloading of chunks, but I have never had this problem with my villagers.