Maybe. As far as I've seen, only people living in nice areas and know gardening have chickens, so they could be good at keeping snails out.
When (if?) I get my own place, I'm going to get chickens for my garden, just so people think I'm living comfortably. I'll probably keep them in my front garden to let passer-bys know as well.
They'll need to be brought in during Christmas though; I'll want to live near a city, and those city neighbours cannot be trusted with chickens during Christmas time.