Hen is acting unusual

[BigBlueHen53]

Since some of your birds aren't laying since they're too young, molting or male, you should get an all flock feed or chick starter or meatbird feed. The last two tend to be cheaper. Just a feed between 17 and 20%(22, tops) protein and calcium levels less than 3.0, oyster shell will also be handy.

I agree. If you have non-layers in your flock, do not feed layer feed, it has too much calcium and is hard on their kidneys*. Instead, provide a dish of oyster shell separately and the laying hens will take what they need and the non-layers will leave it alone. I assume you also have grit in a separate dish available at all times as it aids digestion; all the birds need this. Check your sick bird's crop first thing in the morning before she has a chance to eat or drink, it should be empty. If it is not, report how it feels.

* Edit: a good all-flock formula will work.