I grew up fishing farm ponds in Mississippi and never encountered a live leach until I moved to Georgia. Every farm in MS had at least one pond from a fraction of an acre up to several acres, I think its the law. They are mostly not fed from creeks but from runoff from the surrounding watershed, so no leeches. I think most of us "match the hatch" of whatever the fish in a body of water are eating so I never fished leech patterns or plastic leeches until I moved.