OK, could somebody put me out of my misery please? I searched google images for "duck house", and all I came up with was a load of photos of a certain MP, and a few freaky pictures like the one below!:

So, we're thinking of getting two or three ducks, to help with slug control. We have a decent sized area available, currently fenced to 1m high, mostly grass, with some soft fruit bushes along one side, and a couple of apple trees. Since this area borders the veg plot, my hope is that the ducks will keep the slugs at bay, and can also be given the run of the veg patch at certain times of the year.
My plan is to have a moveable house, with a small fox-proof run attached. The ducks could then roam around the fenced area during the day, and would be coaxed into the run at night with food, before being locked in there and left to their own devices until morning. They wouldn't have a pond as such, but I've read on here that a child's paddling pool filled with water will suffice, as long as the water is changed frequently.
I have two questions though:
1) Can anybody see any problems with this set-up?
2) Does the house need to have a floor? (If grass is OK, I could just move the house every few days and put fresh straw in, before composting the heap of dirty bedding left behind in the old location).
3) Should I go for any breed in particular? (leaning towards Indian Runners at the moment, just because they make me laugh!

)
Any other comments?
Thanks!
Womble.