I agree, Miss Lydia that the yellow could be yolk. I think some TLC and watchfulness and time would be the way to go at this point.That lil bit of yellow does make me think of yolk and maybe you should give him a few more days. you can set him up in a brood box with some water with vitamins or save a chick with heat and stuffed animal for comfort. and keep cleaning that area off with the iodine /water solution. if the lil one doesn't appear to be in pain or acting sickly then maybe just wait and see how it looks even tomorrow.