I would try and feed some oatmeal and millet by sprinkling it in front of her on a dark terry-cloth towel to create contrast, and pecking with my finger at it until she starts to peck as well.
She seems to be no older than three or four days and maybe did not learn yet how to eat, as they need...
How old are the new chicks exactly?
It might be chirping loudly because of stress, thirst, hunger, feeling too cold or too hot or because it is calling for her siblings.