This potential buy I'm going to see this weekend is a 16 yr. Old thoroughbred mare. Her owner told me that she is thin but is steadily putting on weight, although I know that the horse is currently not being ridden. I was wondering, because I've only ever owned an easy keeper, is it okay to ride a horse that is trying to put on weight? I imagine the extra exercise would burn calories, so would I have to feed more then? Thanks!