I had been using a tall plastic canister with a lid that I cut a hole out of. My ducklings are now 6 weeks old and they've started knocking it over several times a day which is making none of us happy. They are about to move outdoors in the next two days. I have a round plastice tub that is big enough for them to walk around in but not deep enough to swim in. Is that sufficient for their drinking water or do I need a separate waterer too? I think the troughs on even the larger chicken waterers aren't deep enough for them to get their bills all the way under? Thanks!