We have raised and released many baby and injured birds....whenever you're going to touch or hold a bird and then release it into the wild, find leaves from any green plant and crush them in your hands as if washing with soap, before you handle the bird. You need to mask the scent of humans as the release-ee may be rejected by his flock or mate if the human smell persists.
Also remember they are not mammals, so never feed them anything milk based. Usually vegetable or fruit baby food is OK, sometimes oatmeal will do too. Wet food, but no water....they can mis-swallow and drown quite easily. They will learn to drink as young feathered birds generally speaking.