Mealworms are very cheap and easy to raise and require little care. I have a big tub of them that I raise for my leopard gecko and spend maybe 1 minute each day taking care of them. Plus mealworm poop is awesome fertilizer if you garden.
If the egg shells are finely crushed so they no longer...
You can start introducing them to other foods in fact you can start much earlier than 5 weeks. Leafy greens, tomatoes, apples and meal worms are great to supplement your chicks/ducks diet. Cracked corn one the other hand doesn't have any real nutritional value so I wouldn't give them too much. And