Looks like a bulging hemorrhoid rather than a full prolapse.
Is her abdomen swollen and squishy(water belly - ascites)?
I'd isolate the bird in a wire cage within the coop for a day or two....so you can closely monitor her intake of food and water, crop function(checking at night and in morning before providing more feed), and her poops. I do this in the coop building so she can stay with her flock to avoid reintegration issues..
I like to use a fold-able wire dog crate (24"L x 18"W x 21"H) with smaller mesh(1x2) on bottom of crate under tray.
Then you can put tray underneath crate to better observe droppings without it being stepped in.
If smaller mesh is carefully installed, tray can still be used inside crate.
Sounds like infection, look up 'lash egg'.there was a white plug, very cheesey looking,
Is her abdomen swollen and squishy(water belly - ascites)?
I'd isolate the bird in a wire cage within the coop for a day or two....so you can closely monitor her intake of food and water, crop function(checking at night and in morning before providing more feed), and her poops. I do this in the coop building so she can stay with her flock to avoid reintegration issues..
I like to use a fold-able wire dog crate (24"L x 18"W x 21"H) with smaller mesh(1x2) on bottom of crate under tray.
Then you can put tray underneath crate to better observe droppings without it being stepped in.
If smaller mesh is carefully installed, tray can still be used inside crate.