Fluids are more important than eating. If she does want food, you can add water to the feed in a small bowl, or to any egg or treats. Most chickens need 15 ml per pound up to 3-4 times a day. It is safer to hold a small cup or scoop up to the beak, and let them drink on their own. You can dip the beak into the water for a second to give them the idea. If she won’t drink, you can carefully syringe water into her beak a few drops at a time, letting her swallow. Tube or crop feeding is also a possibility, but that should not be necessary until she keeps refusing. It is usually done 2-3 times a day.