When hand raising a baby bird you can take several peices of dog or cat food and add enough water to turn it into a paste.  Using a straw cut to a beak like shape, scoop some of the paste on the end of the straw.  When the baby bird raises its beak for food, simply squeeze the food into the birds mouth.  They need to be fed every several hours.  It is helpful to know what type of bird it is.  If the bird is a seed eating bird this works well.  I have raised several and relased them back to the wild with this method.  If they are birds that eat insects you can use flys, raw hamburger, or small crickets.  Hope this helps.  Good luck.