I am growing fall lettuce right now and my snail/slug problem has gotten much worse. I have heard that bringing in geese and ducks to munch on them for 10 minutes a day or so can really help. We live next to a public park with a small duck pond and I am sure I could convince them (herd them) into my yard in the evening for a little bit of time. My question is regarding the feces that they may leave behind and any other side effects you may anticipate coming from their integration into my garden.

I really want to avoid all chemicals so am trying everything else first.