Ducks being scared by firecrackers

[dido123]

Today some idiot threw a firecracker into my yard. Made a pretty big boom and I could see the flash through the window.
My two ducks (male and female) got very scared and ran under their pen. After the female duck was shaking (something that had happened before, not due to loud noises though). I gave em some food to calm down but soon more firecrackers started going off in the distance which made her start shaking again.
I'll keep em inside for New Years Eve, but I can't do that for a whole week - the smell would be terrible.

Any tips?, I know it's a danger to dogs, but can loud noises/fear harm a duck?

 

[nuthatched]

Call the local authorities and set up cameras. Keep them away from your fence

 

[dido123]

Call the local authorities and set up cameras. Keep them away from your fence

Police won't do anything even with camera footage.
There is a second fence inside which the ducks are that's 10 meters away from the "outer" wall/fence.

But yeah, unfortunately there's not much I can do to stop it. Has it ever happened that ducks got hurt because of this kinda stuff?