American Guinea Hogs are a heritage breed considered to be threatened by the Livestock Conservancy.
Once a common homestead pig, there was (and still is) a lot of variety in the breed. They have upright ears and curly tails, and while most are black, other colors, such as red and blue, are possible. Hogs are generally between 100 and 300 pounds with butcher weights of 100 to 125 pounds. Guinea Hogs do well on pasture and have a docile temperament which make them ideally suited for small farms.
From the Conservancy description: Guinea hogs have uniquely desirable flavor characteristics. The fat of the Guinea Hog is abundant and firm, and has found interest with chefs and butchers for making charcuterie (old world style cured meats). Their rendered lard would be of particular interest to pastry chefs for use in crusts and dough. The have an exceptionally tender meat and produce fine hams.