Finally, the little duck came out and tried to keep up to the mother and the two other little ducks, who were at least two days older than the new one. To warm up the baby, I gave him to the new broody chicken mamma. She readily accepted him under her already crowded wings and warmed him. I left him there for the day. By the day's end, the duckling sat pining for his family and was much stronger, so he was returned to his mother and siblings. As she waddled away, little duck was able to keep up to her. All will be well.