I have. There's a nest near my house that a pair pigeons populate each year. One time I unsuccessfully tried to save a deformed chick that fell out. Didn't live.

You know birds don't leave their nests till they can fly right? At which point, they look like adults (except for very slightly smaller size). That's why you don't see chicks unless you go looking for nests.

At this point you aren't even trusting your eyes, yet believing suggestions from others. How's your own sanity?