If she was starting a molt, she may stop laying for awhile. I would try to get her eating mostly the layer feed, and you can put a little water in some daily made fresh. It has more protein, is more balanced than corn or seeds and grains.
Could she be starting to molt? She is the right age, and looks a bit like it. I would continue to observe and offer mushy wet feed tonight and again tomorrow. Let us know if she has any other symptoms.
How old is she? Does she lay eggs? Is her tail up or down? How does her crop feel? What does her poops look like? Can you offer some sugar water or electrolytes up to her beak? Then some mushy wet chicken feed, scrambled egg? Getting a baseline weight on her in the am might help. What do you...