Here's what I do.
Get a bin or aquarium and put some organic soil in the bottom. I mix in about 25 percent sand. Keep the soil moist. Put the largest snails in there and they will mate and lay eggs. I then remove the eggs to a new bin and discard the old snails when you're done with them. The babies will hatch in approximately two weeks. I feed mine romaine lettuce,carrots and such.
All my Chameleons LOVE snails.