Originally Posted by Sunny
If the saddle is shifting to the side, it's probably too narrow. Good luck with your new friend. :]
Posted via Mobile Device
It could also be too wide. :) The saddle I use on Lacey shifts all over the place and that's because it's documentedly too wide for her. But it could definitely be too narrow.
OP: if you're aren't sure how to properly fit a saddle, you could take pictures of it, front and back and a side shot, all with the horse's head up, and then post them. There are quite a few people on this forum that are great at determining if a saddle fits right or not. :)