Often times, it is best to make sure the mare and foal are already in a group of other mares/
foals,and when separated, the foal will continue with the other
foals, and the mare will remain with the herd she knows, lessening the separation anxiety (although it is sure to happen). At this point, the horses together will always have a strong bond, especially if they are the only horses in the pasture, and will have continuing anxiety at any kind of separation.