That is a pretty bad case of pasty butt. You need to get that off.
Soak a paper towel in warm water and really soak that mass. You may want to squeeze the hardened poop with your fingers. Don't worry. You can wash your hands!
Once you get that off, use a soft towel to dry her well.
She also looks backed up. I would try to get 1/2 tsp of coconut or olive oil into her to help her pass what's in her. Room temperature coconut oil is solid and she may pick it off your fingers. Otherwise apply a drop of oil to the middle of her beak below her nostrils. When it flows down her beak, they usually drink it. Go slow and careful and get as much of the 1/2 tsp of oil in her as you can.
Inspect the rest of them for pasty butt too.