Welcome to BYC. How old is she, and has she been laying eggs recently? When I have a sick bird, I feel of the crop for fullness, emptiness, or impaction, then feel of the breast bone for weight loss, feel for swelling in the lower belly, look over the skin around the vent and other places for evidence of lice, mites or eggs, look at color and consistency of droppings, and offer them vitamin/electrolyte solution to drink. Is she having any problems walking or does she stand hunched or puffed up? Has she been de-wormed recently?