After 10 days the second dose is to get any newly hatched worms since the Valbazen doesn’t kill larvae. But yes try to get as much of the droppings as you can. It is a good idea to keep droppings cleaned up as well as possible unless they are out free ranging in an open area of grass. They may get exposed to worms again, but the treatment at certain intervals can keep them from having a large worm load. The intervals once or twice and year or more often depends on your environment. Dry stirred bedding, and having a large area to roam on is helpful.
