The ducklings that were a week behind my other 2 started hatching yesterday and while I was gone made its way half out of the shell. We were all excited while watching it until my daughter noticed that the yolk sac is still outside of the duckling. I don't remember where I saw this but I got a wet rag and wrapped the duck and the egg in an upright position in a little cup and placed it back in incubator. Is that what I do???
I'd remove the damp towel as that might chill the duckling. Otherwise things sound good, get it in a cup that it can't get out of and prop it up in its shell to let it finish absorbing everything. Make sure the humidity in the incubator stays nice and high so that things don't start to dry out.