You could use regular adult size grit, and just put a small amount in a small dish or lid for her to take as she needs it. So her crop feels like a water balloon, or is it firm? If it is firm, then massage it several times a day. Has her crop been enlarged for awhile? She might be dealing with a...
What treatment have you been doing so far? What do you feed her? Does she have granite poultry grit available? The tracheal cartilage in the front of the neck is a stiff pipe that protects the airway. Could that be what you are feeling? Her crop looks pretty large. Is she drinking a lot of...