I looked at these and guessed they were some kind of half shoes for side weighting. I was wrong. They're oxen shoes.
Any of you guys have some ox on your books?
http://i248.photobucket.com/albums/gg181/msgough/Blacksmith-Shop/IMG_0039.jpg?t=1225770821
Bob shared that he was told these shoes were made to deal with stifle problems. Basically, the horse won't put full weight on the leg that has this shoe on. Can also be used to make a horse put weight on the opposite foot.
http://i248.photobucket.com/albums/gg181/msgough/Blacksmith-Shop/IMG_0040.jpg?t=1225770967