The frostbite. All parts that were frozen are damaged, those are the pinkish, and dark scabby places. The tissue that is damaged enough will die, turn black, and fall off. If there is still circulation to some of it, it may recover, but I would guess all those spots will eventually die. At the base of those areas the tissue will swell as the foot tries to seal them off to heal. The birds were probably attracted to the redness of the damaged toes, and that is what caused the pecking.