Take a plastic cool whip of some other kind of plastic container cut the container the size of the ducklings foot, wrap vet wrap or some tyoe of tape around the shoes to cover sharp edges. Lay the feet on top of the shoe and wrap the entire shoe and foot with vet wrap. Making sure it's snug but not tight enough to cut off circulation. Check every few days to see how progress is coming. You can also make a hobble for the legs to keep the legs at the right angle under the body. I'll get you a link.