I have a situation at my barn. A boarder friend has started riding her horse alone and away from the barn. This leaves two horses behind, which should be fine right? NOPE. My horse is very attached to my boarder friends horse and runs the fence line calling for her until she comes back. This has been going on for about five weeks happening about three times a week. No improvements on my mare's behavior. I'm getting increasingly worried that my mare is going to hurt herself. Does anyone have any advice? Things that have helped or will I just have to tell my boarder friend to stop riding out alone?