I haven’t done a lot of research on this subject but I’m knowledgeable enough to know that shoeing horses now is not a whole lot different than it was back then. Yes, there are some farriers who cut the horses foot to fit the shoe, but a good farrier shapes the shoe to fit the horse. See where I’m going here? If you have six horses being shod, every horses foot or hoofprint will look different. No two horses are exactly the same. A good tracker will be able to tell which hoof belongs to which horse just by them walking away. There are no ‘factory feet’, so he would be able to tell by the shape and size, and also by how the horse moves. Every horse moves differently. Some move with big, long strides, while others are more choppy. I hope I was able to help. Good luck with the book.