She may "feel" full due to the pressure of the babies on her stomach. I would suggest giving her very small portions, and yes, you may have to do this by hand, several times a day. How long has it been since she ate? Is she eating anything at all?
Another question is has she been using the bathroom? If she is constipated that can only make her even more full. Maybe try a very small scoop of plain yogurt on top of a 1/4 c of dry kibble?