Urgent Swollen butt area

[Teiley]

Hey, my aunt has a female cockatiel named Tieley and for the past few days she's been lethargic and sitting at the bottom of the cage during the day and coming up during the night. She shares the cage with her male partner. Recently we found a huge blob of poop stuck on her butt area (two days ago), there is a vet appointment for next week but figured any advice is helpful. Another thing is that when she breathes, her entire tail feather area pulsates. Any and all help/advice is really appreciated.



Her butt area is wet cause we make sure to wash it with warm water in case there is poop stuck on her butt.