What's wrong with feeding multiple mice? Does that mean I'm lazy and take short-cuts because all 45 of my Ball Pythons eat mice? It all adds up, weight-wise, so it doesn't matter if the prey is mouse, rat, ASF rat, jerboa, whatever.

You are correct in saying the OP does take alot of short-cuts with his snake, it's his first snake and he likes to assume he knows better than people who have had hundreds, if not thousands, these snakes for 30 years or more. But anyway!

The bark will pass through and the snake should be fine. If you're worried, use newspaper for bedding or fine-shred aspen. Remember, they can digest bone, so a little cellulose, which is likely already in the mouse's stomach anyway, isn't going to hurt anything.