I have a Thoroughbred mare that panics when she can't see the other horses. Leaving the other horses out is not an option as the grass is rich and they are already putting on a lot of weight... She desperately needs to be out on grass as much as possible because she needs to gain some weight. She won't eat more hay throughout the day. Upping her grain is not an option.
She isn't out more than a few hours. When we bring the other horses in she is ok for maybe ten or fifteen minutes but once she realizes they are actually gone she goes into a panic and runs the field.
My question. Can I leave her out in the field in hopes that she will relax on her own? I don't want to set her up to injure herself, but she really needs to be out longer. She doesn't try to run through the fence or jump it or anything... just runs and runs. Her pasture isn't far from the barn.