They do need poultry grit available all the time, it's crushed granite in the correct size for poultry. They can't grind food up in their gizzards without it, they can get impacted gizzards. Sand won't do it, and oyster shell and egg shells are for calcium, not for digestion. Some...
Do they have access to poultry grit all the time?
An impacted crop will feel full, and the mass won't pass. It's usually something foreign they shouldn't have eaten or it's often a lot of fiberous plant material, like long grass, that they can't pass. Since her crop isn't full, it doesn't...
How old is she? Do you know when she last laid? How is her weight, is the keel bone well muscled or is the bone very prominent? What do her droppings look like?