I really feel like this is a case of internal laying, which is caused by an E. coli infection. It can be treated with prescription-strength antibiotics, but you'd never be able to eat her eggs again (they say).
Do you have any other birds with these symptoms?
If she's passing thick white/yellow poop, that's a pretty strong indication.
I would do some reading on Egg Yolk Peritonitis (internal laying) and see if that matches anything else she has going on.
I don't mean to sound so cold and clinical, but.... if she passes (I hope she recovers!) consider sending her in for a necropsy. You can contact your local vet for information on where to send her for your state's USDA branch to determine cause of death. It's free, outside of shipping. If she passes (I hope she doesn't!), you can wrap her in some plastic bags and place her in the refrigerator until you can ship her. That way, you'll know for sure what it was and can plan accordingly to move forward with a plan for the remaining flock.
I am sorry about Vaneeta.
Edited by MrsBrooke - 4/6/16 at 9:54am