I'm hoping this thread is a clue to what's going on with a my two year old Delaware. A couple months ago I noticed Lizzy had a mucky backside. She acted otherwise normal. I have treated the poor hen by separating her out into "the hot zone" (which she really hates!), given her antibiotics, treated for possible gleet (we won't go into those details) and wormed her.
Finally the whole "jelly belly" business clicked! While acting otherwise normal, eating etc, but NOT egg laying at all, her abdomen is tight and "squishy." I did a chicken to chicken comparison and her abdomen does not have the normal, loose, chicken skin appearance of the others. It looks rather distended, tight and shiny, and is blotchy grey/pink/yellow looking though the skin on the inside, if you get my meaning. She is still a little dirty (poopy) in the back, but that is better. Now I'm thinking yolk peritonitis, the sterile kind or she'd be dead by now.
So, if I understand your posts, it's just wait and see if it's re-absorbed? She really acts normal otherwise, no blueish comb, no funny walk, no apparent discomfort, just a mucky backside, swollen belly and no egg-laying. I don't plan to try to drain her unless she seems distressed, as I don't want to risk introducing bacteria.
Thoughts anyone?