I will try to post pictures tomorrow, I don't have any at the moment. She gets 3 1/2 scoops (using a regular sized coffee can) of Blue Seal Vintage Senior, Probios powder in the morning and corn oil in the morning and afternoon. Since I have never bought a saddle before and this was a gift, I asked my trainer to make sure it fit. She said it did. I'm using a fleece saddle pad, but I've always used fleece and it's never happened until now. I'm stumped

The one I've used lately I borrowed from another boarder, could it be from their horse?