Good job on the boy and good pics too. I`ve seen stuff like this with chickens marked with zip ties. Neglect is pitifull. I would hold off on the iodine unless you see any infection. Also, the spur trim might be easier on him if it has stopped bleeding for a few days. The potato method is recommended by a lot of folks. I haven`t done it. I have however gripped the spur with a plier and twisted it off. Use a quick twist and a little snap and it`s loose. The quick inside will harden in a few days to form another smaller spur. Also, cutting the spur with a Dremmel tool is good. In this case, cut the spur about 3/8ths to 1/2 inch from the leg. Common baking flour and a little pressure will stop any bleeding. The good part is that the cut off wheel on the Dremmel tends to cauterize the spur. When you set the boy down, he will act like nothing happened. When the wound stops bleeding and his swelling is looking better, get him out on the dirt so he can use that foot. That will do a lot more good than a cardboard boot. He should be fine as long as infection doesn`t take over. Good luck........Pop