OK, years ago when we lived in WA and hatched all of our own brids (ducks, turkey, geese, chickens...) we had a duck hide a clutch from us and hatch them out herself. We had great mama's so it was no biggie, our dad just liked doing it himself...anyways they were mallards and once they got to be about the age to start getting feathers we came out one morning to feed them and every last one was dead in the water dish (one of those heavy duty shallow black ones that are like 18 inches across and 4 inches deep) and we never knew what happened. Is this something that happens to ducks??? DO they all drown together? Also, do the drakes often attack the new ducklings cause ours would flip them over on their backs and peck thier belly till the baby died if we didnt keep them seperate.