I can't tell from the photos, but does she have any swelling in the toes or feet or legs?
Unfortunately, these symptoms can be from any number of disorders, from relatively simple and easily treated to very serious and deadly.
Things you can treat for are stress, hypothermia, or dehydration by giving her some electrolytes with sugar water. If she revives, then it was likely one of those. She could also have a respiratory illness called Mycoplasma synoviae, so you could get some Tylan or Tylosin and treat her with that and the symptoms may improve.
If she declines, gets worse, can't hold her head up and eat, she might have an avian virus, Marek's or Leucosis. Those are not treatable and would have consequences for your entire flock.
I've been treating three pullets for similar symptoms and recently learned from having a necropsy on one of them that she had avian leucosis which caused misery throughout her little body including her brain, accounting for her lack of balance and paralysis. Necropsy is about the only way to know for sure what is going on with your chick, but try those treatments before jumping to the conclusion it's the worst scenario.