You can feed a baby bird a commercial hand-feeding formula, which can be purchased at pet stores or online. It is important to follow the instructions on the packaging carefully. If you are unable to obtain a commercial formula, you can also feed a baby bird a mixture of softened dog or cat food, moistened bread, and hard-boiled eggs. Be sure to feed the baby bird using a syringe or dropper, and consult with a wildlife rehabilitator or avian veterinarian for guidance if needed.