slugs seem to come out at night after my ducks are in the kennel for the night for safe keeping. the slugs get into the ducks food and eats it and leaves behind a slime trail in it and the slugs have a lot of little parasites running all over them. will the slime trail hurt the ducks when they eat the food in the morning? does anyone know if they think the little parasites get off the slugs and stay behind after the slugs leave? what's a safe way to keep slugs out of the pen at night?