The leather I use is mostly cow leather. The cows are bread for beef and dairy use, many left over skins are then turned to leather. There is more leather available than is used, this helps to keep the price reasonable. The best craft leather comes from areas where the stock has steady climate and feed. Breeding does contribute but we have little opportunity to select. Typically a crafter will hand select a piece of leather for a particular job. I believe that Leather crafted in the country of origin is best as it does not have to endure quarantine process that does cause some damage and because the best selections are always kept in the country of origin.
