Starting with ducks

We have a ridiculous slug problem here - the lawn is crawling with them, and they are like something out of a horror film (I tried drowning them in a big tub, only to see 20 or so slugs emerging from the water and climbing back out! eeuuurgh!).

anyway... a permaculture book I'm reading says it's not a question of having too many slugs, but not enough ducks, and that they would be the answer to the problem.

Does this sound feasible - they would be kept in a run of electric netting as a fox has recently started visiting. We have a broody coop going spare, would that be OK for 2 or 3 ducks to sleep in at night? I've also read they can eat layers pellets, is this correct?

And how to solve the problem of giving them water to swim in? Does it need to be running water, if not how often would it need to be changed? How deep would the container need to be?

The book suggests either Khaki Campbells or runner ducks as being the most carnivorous.

Sorry for all the questions, but a google search gave a lot of differing opinions!

I have runners and a couple of cuyaga crosses (from kate!) the first thing they do in the morning is wander off on a slug hunt! yeuchhhhh!!!

Have to confess that I am not a big fan of Campbells. They have a great reputation as layers (mine have obviously not heard that!) but also for being very nervous which mine certainly are! My silver Appleyard is much more beautiful, a calmer, happier duck and out lays them hands down! She was also a great broody and mum, restarted laying about 4 weeks after hatch and has misses 2 days in about 6 weeks since. Would recommend them to anyone.
I also have some Welsh Harlequins that have a great reputation as layers (mine are too young to have started so can't offer an opinion there) but are very beautiful and less nervy than the Campbells despite being younger and raised by a broody and therefore not used to being handled.

And then there is Patrick, my Cayuga. He has the nicest temperment, his offspring are also very friendly despite being crossed with my Campbells. All to young to know if they will lay well although Cayugas are not known for that.