I have a very small patio with a few
rose plants in pots. No place for geese, ducks, or
chickens.
I have used the dishes with beer. I find the darker beers that have a sweeter/malty taste (as opposed to the more bitter/hoppier) attract the slugs better than domestic american crap. I think the slugs must have good taste. The important part is keeping the beer warm and only slightly stale. Too stale and they don't like it. Also the more pungent the better.
I have also tried the manual scraping the slimy guys off the plants. This is more time consuming, but more effective. I had a serious issue and not enough slugs were coming to drink at the local beer joint and I had to manually kill a bunch.
This year, I plan to get some pliable copper tubing and make a barrier around my pots. Slugs won't cross the copper because it's toxic to them or something.