I had no idea it even mattered!
I have a horse calendar with little "fun facts" that says all horses have 2 legs on one side that are slightly shorter than their other two legs...and the side the mane naturally falls on is their shorter side. I've also heard others say that it falls on their "stronger" side...who knows how much of either is true.
Sandie's falls on the left side, and I hadn't really thought of switching it...I would think that would take a LOT of effort!! Are there rules on which side it's SUPPOSED to fall on?? I've never heard of this...I always thought it just falls on whichever side is most natural and is just another personal characteristic of your horse.