I once had a mare that had two completely different front feet! Good farrier, vet even xrayed, it just happened that her front legs were not the same (yes, she was VERY fugly.. never bred!). She stayed sound until retirement when she limped a bit. She's now at my friends farm, keeping the newly weaned UNfuglies company. She is in love with those little foals... even if they try to nurse!