Ideas for collecting muscovy poop

Dear all,

I have 16 muscovy ducks at my small farm. They mostly stay around the pond and at night they stay at the edge of the pond.

I would like to utilise the poop and my idea was to build an enclosure for them where they could stay at night and then cover the ground with rice husks to collect the manure.
I moved their food tray inside the enclosure to feed at 5pm and then closed the "gate". Feeling at bit bad since I know they like to bathe and clean themselves in the pond after eating in the afternoon.

It turned out that they were really not happy with staying inside the enclosure during night and eventually they all got out to their usual place on the edge of the pond or the small jetty.

I have covered the edge of the pond with rice husks but I don't think it will be easy to collect.

Any ideas of how to do something that will allow me to collect the duck poop?

I have attached photos of how it looks at the moment and where they like to be at evening/night.

Thank you!

Since they seem to really like the jetty, perhaps suspend a tarp or float a tray underneath the dock.

Or perhaps note where they tend to spend the most time, and construct a comfortable slatted wooden platform over the water's edge with a tray or bucket underneath it so manure can be hosed down into the bucket. Floating platforms are always fun, too.

Or maybe collect the manure inderectly via aquatic plants soaking up the nutrients, and used them as mulch or fodder.

Beautiful place, Mark.  

I like George's suggestions.  Let us know what works.

@George Yacus - thanks for the suggestions. I have been thinking to place a tarp of some sort on the jetty to collect. Now the young ones have learned to fly and they not spend their nighttime on top of the small building next to the pond!

@Timothy Markus - thanks, I will! I haven't done much on it yet.