you did awesome dealing with this issue, and we are always happy to be her for moral support, offer suggestions or bounce ideas, and if need be holler at someone who knows more than us
A day of electrolytes might be in order, it sounds like the clock is molting which zaps them sometimes especially if they are lower on the pecking order.
What is the age of your hen?
Has the flock been de wormed?
What are they being fed by you, including treats?
Has she been laying eggs normally?