What can I feed a BRAND NEW hatchling chimney swift which fell down my chimney?

The nest fell into the fireplace. We attempted to replace three others by placing them with the remains of the nest in a plastic bowl and positioning it above the flew. We then closed the flew. I just found a fourth baby. It has no feathers, and its eyes are closed. It is crying. I hate not to try something, but I'm afraid to disturb the "nest" we tried to replace, because I have been hearing the mother/father coming back to it. Help! Is there anything I can do for this baby?