Ducks eat Japanese Beetles!!
My chickens don't eat Japanese beetles but I have been talking to some waterfowl people and ducks scarf them up!! My order is in for Spring delivery of 10 ducklings.
Best for pond clean up & pest control are list as:
Runners, Hookbills, Campbells, Harlequins, Magpies, Anconas and Australian Spotted Bantams.