Why does my hamster eat its poop? Is this normal or healthy behavior?

Hello there! Unfortunately for us, this is a very normal behavior for rodents. The medical term for poop-eating is coprophagy, and in hamsters, it's healthy for them to do so. Many animals, like rodents, that eat a mostly plant-based diet don't get all the nutrients from their food the first time it passes through their digestive system, so they literally digest it a second time by eating their feces. This helps them get as many nutrients out of their food as possible. I hope this helps, and that Willy stays a healthy and adorable friend!