I visited a snail farm recently. Chappy there has to do a nightly slug patrol in his "paddocks" to make sure they don't come and scoff all the food he puts out for his snails. He says slugs emerge half an hour earlier than snails and can scoff huge quantiies of their special grain so he just cuts them in half with scissors and has a small terrier for chasing the inevitable rats.
Personally, I use the wildlife friendly slug pellets but also chuck any snails and slugs in the road outside where passing traffic squishes them instantaneously.
