I will also try to open its beak and take a picture of the inside and post it here... it is quite dark but i was not able to notice yellow/white but will check again later. Giving both of them pcs of ginger.You have to take care not to overdo the antibiotics. She cam to you sick with symptoms. She may have mycoplasma a chronic respiratory disease. Symptoms may come and go—it is a disease for life and she is a carrier. Overuse of antibiotics can lead to fungal overgrowth.
If you see any yellow or whitish material inside her beak, that could be something like canker or another problem.