If the defect (hole) in the part is small enough or the path length for the leak is long enough, it will be almost impossible for the fluids to flow through the hole (leak). The fluid properties that affect flow are pressure, temperature, and viscosity.
Though the answer seems to be correct, but when taken from that perspective, one will not keep focused on the real reason. The main reason why we shoe horses is for work, which then determines the style and the type of shoeing for the individual working horse. Various types of historical horseshoes.
The natural diet of the horse is grass. Grass contains most of the nutrition a horse requires to be healthy. It also contains silica, which is important for dental health. Primitive horses can live on sparse rations and often have to make do with less than ideal pasture and living conditions.