How old is she?
Does she still lay eggs, or does she go to the nest like she wants to lay eggs, but doesn't lay anything?
How long has she been swollen like this?
Is her poop normal, or does she have diarrhoea (if you were washing her then I guess she was probably dirty from diarrhoea?)
Is she eating / drinking / moving around?
Have you checked to see if there is an egg stuck inside her (eggbound)?
Does the swelling feel soft like a bag of water, or hard, like solid flesh?