I would try to soak her vent area, and also try to examine the vent (put on a disposable glove and lubricate your finger) to feel if there is lash material, hard droppings, or possibly tumor inside. Solid droppings can be removed. Hard to know if she may has an obstruction, vent gleet or what. Some coconut oil, chilled and cut into pieces to eat, or some mineral oil put into a little food or egg might help to soften hard droppings. It looks like it might be time to think about ending her misery if the soaking and treatment don’t help.