Whenever there is a change in consistency and color of droppings something may have changed in GI system. New foods or new brand of foods? You could add the ACV to drinking water for one week and see if any improvement. 2tsp of unfiltered apple cider vinegar to 1quart water. If not better i woukd consult with avian vet. Could be an infection of sorts that needs treatment. The droppings do look nor mal.