Basic hoof shapes are oval to round and pear shaped, and should be cylindrical, without flares, hollows, bulges or distortions. The basic components making up the hoof, are the frog, the sole and the wall, which is readily see from the bottom of the foot. Where the wall and sole meet, there is a distinguishing line called “The white line”.
Generally speaking the hoof is sensitive from the white line in towards the frog and insensitive from the white line out to the wall. Much is made of nailing outside of the white line in order to not quick the horse, and this is definitely a major consideration when shaping and then nailing the shoe on. The true shape of a hoof is determined by the “white line” of the sole. This white line stays true – a factor that requires clear understanding of what is a “true” and what is a “false” white line which means that the hoof has not been allowed to flare or is not in the state of “founder”.
If a shoe is shaped to the irregular perimeter of the outside wall there is no control over the irregularities of hoof growth. Why? Because the shoe has been shaped and nailed to these irregularities and therefore encouraging them to continue to grow in that fashion. An experienced farrier will dress the hoof so that these flares and iregularities are removed and uniformed growth is encouraged. This might take up to a year to accomplish but is definitley what all competent farriers attempt to achieve.
Shoes should never be nailed to flares or wings that occur on the hoof wall. This will not be a strong setting and the true foot size will be distorted. So the shape of your shoe should follow the shape of the white line, providing the hoof is normal. That means cylindrical, with a true white line and all distortions removed.
The other factors determining shoe shape are gait problems, e.g. breakover, brushing, forging etc., and can entail quite a variety of shapes and configurations in order to accomplish the maximum performance from your horse safely and comfortably. This is a study all by itself and would be impossible to outline in its entirety here. The subject that we are addressing here is shoe shape for the average, normal hoof.