Old maiden mares are considered special mares with the possibility of reduced fertility. An old maiden mare is a mare that is older than eight or nine and has never had a foal. However, there are other mares that are in the same category; mares that are bred at the age of two, foal when they are three, and then go into a show career and are not bred again until they are 12 or older behave very similarly. Not all are the same, but they are all at a higher risk of being a problem.