Lower a strong cotton (edit: or some textile, something strong and thick enough) bag into the hole, with the rim of it held open by a strong wire. Large enough

Lower a strong cotton (edit: or some textile, something strong and thick enough) bag into the hole, with the rim of it held open by a strong wire. Large enough for the puppy to climb in, put food in there and something that smells human maybe. Best make the bag a longer tube. Hopefully the puppy will climb into it, getting the food - then try to pull the whole thing up.