My husband wants to get 2 ducks. I have heard and read that they are messy. The ducks will be staying with our chickens in the coop and run. The coop is 4 x 8 and the run is 8 x 8. There will be 7 hens. So what is "messy" when you have ducks in the mix? Any thoughts and guidance would be much appreciated. Also wondering if ducks will use the same nesting boxes as the hens?