Our foaling stall is 20x20 but we have had to use our 14x16 and our 14x12. They have all worked out pretty well. I would probably choose the stall/paddock at the end simply so that your mare will only have another horse on one side. It might make her feel a bit safer not to have a horse on each side. If you leave her where she is she will feel the need to worry and protect the baby from both of her neighbors.
Mejoramiento de Busto Miamii