I have heard this before. Do you think it's the same with horse/donkey combos?I heard, from a lady who keeps two mini donkeys, that you MUST have them in pairs. They do not do well alone. I don't know if this is her opinion, or the truth in like a FACT, but I wonder if it applies to mini mules, too.
I would speak more with folks that own mini donkey/mule horses. of course, you may find some here, but I mean, what such owners have to say will be more appropriate than just what general horse people might say.