The corn is only 42 percent digestible and has a protein of less biological value than that egg, and the amino acids are not properly balanced for omnivores. So comparing two diets solely on the basis of protein levels is highly inaccurate. Most of the baby birds that come into wildlife centers are dehydrated and suffering some degree of starvation, after hydrating we feed the dog food diet, without problems. Starved babies need the proper nutrition, perhaps more than healthy animals. Never give a baby earth or fishing worms.
Worms can carry parasites that are harmful to baby birds.
Use natural tree branches for perches, the dowels are not good for their feet. They enjoy toys such as small plastic whiffle balls or things they can throw around, especially shiny things. They should have some natural sunlight each day or a Vita light.