No, I don't recommend it. Most of the time, the mother will attack it if you try to put it back after too long. However, I have had some success with returning or giving a duckling under 3 days old to a mother with ducklings the same age. You have to be extremely careful and be prepared to re-rescue the duckling if the mother duck tries to kill it. I wouldn't try this unless you know exactly what you're doing and know duck behavior extremely well.