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.
When you do things right, people won't be sure you've done anything at all.
For me, they ate all my strawberries exactly the second that they were ripe. I only could gather twice a day, before and after work. The slugs could wait all day and all night, and chomp at the perfect time.
If they left my strawberries alone, we'd all live in peace and happyness. But when they ate all my strawberries, every day, after all the work I put into the patch, planting, fertilizing, weeding, watering, etc. this means war.
Slugs are my number one enemy. I tried all sorts of things except duck or geese. I kill at least 10 a day. I tried salt but the wrong way, I spread salt on plants and they died. I want to try beer but not sure my puppy would leave it for slugs.