This is the crop. It will fill and empty throughout the day as she eats and drinks. Some birds really stuff their crops, some eat less more often. They will usually have something in their crops when they go to roost at night and will digest over night, so in the morning it should be empty. If it's not empty, if it feels very hard, or very soft and squishy, then that could indicate a problem. Just cup your hand over it from the outside and feel/massage it. You won't hurt anything. If it's very full, don't squeeze so hard that you make the bird regurgitate.