When you can see your worms moving and looking healthy, chances are they're happy. Their poop should be fairly worm-shaped and not clumped together or caked with old straw.    They should also eat whenever you offer food to them and poop within a few hours of eating it. Worms that don't move, don't seem to notice when you poke them, or have been sitting in poop for a few days might mean that something is wrong with the container's conditions.    Either the temperature is too cold or too hot for their health, there might be something blocking access to food (think plastic wrap), they've become dehydrated from lack of water, etc.