You have to get use to giving your chicken "chicken feed". So, set their feed tonight, they will get use to if eventually because no matter if they like it or not, they got use to something else, you got to bring it back, so by giving normal feeds to them, they shall get use to in a couple of...
If she suffers from diarrhea, or any type of common disease, I recommend you spray some cinnamon powder into your chickens feed.
There is a lot of natural cures, cinnamon is one of them.
Is your chicken suffering from a cold shake? Or maybe even a trauma that cause her to lose her appetite...