will that cause seemingly perfectly healthy ducks to be fine at night at lockup and dead the next morning? the pond is completely drainned now and yes, mosquitos galore. other interresting note. day after the second duck died, the gate to their pen was unlocked and left open a crack. now, this is NOT an easy feat. this gate needs to be kicked open and the lock is always jammed. my kids did not do this and i know for a fact i closed the gate when i left. starting to wonder if the ducks had help from humans in their early demise.