I would have your farrier take a look at her feet. He might be leaving the inside of the hoof too long causing her to clip herself when she travels. Also, how is her conformation? Does she has slight crooked legs, or does she toe in at all?? The key would be to get with your farrier and let him/her know that she is clipping herself, thus he/she can trim or change the angle of her foot so she can't clip herself.