@azygous @Wyorp Rock
Feel her neck, do you feel anything she might be choking on? Was she just eating when you saw this? Sometimes they do this when they scarf down food to fast. How long has this behavior been going on? How does her crop feel? Hard, flat, soft, doughy?
Is her crop emptying overnight? To check, feel her crop before you lock them up, it should be semi full. Remove all for and water from the coop, and before you let them out in the morning, feel her crop again. It should be flat.
Can you weight her? If her crop is flat during the day, that means she's not eating.
Can you also check her legs? Th bottoms of her feet, look for bumble foot. Feel her legs up and down for any swelling, heat, or tenderness.
Can you get a photo of the "little black bumps?"