Okay, then maybe it would be good to intervene because if she's not eating she'll waste away. I'm thinking the fluid build up is probably peritonitis (although that doesn't really explain the soft shell although it could be hit or miss). It could be ascites but I don't know much about that.
Has she been laying up until now? It might be best to try a feel inside (might as well give her a bath while you're at it). I like to use the Adam's Plus Flea and Tick Shampoo and follow up with the same in spray. I'll use a q-tip under the wattles and around the ears. You ever give a chicken an ear rub?
If you don't feel anything (if she's peritonitis you won't be able to feel far) and in either case some oral antibiotics can reduce the symptoms of peritonitis.
There is a fluid draining process some of us use with a large needle and syringe and I'd recommend using it with antibiotics as well. It might be something to think about but you can try antibiotics for a few days. You always want to drain on the right side. There's some good threads on the subject of "how to".
In the meantime you'll have to be proactive about getting food in her because they tend to just waste away like that. I have one right now I'm always favoring with the orchard's bounty and I pull her aside once a day and feed her something with some antibiotic sprinkled on.
They also tend to not take care of themselves you you'll have to be proactive on the delousing. You should think about a worming program if you haven't already. You should keep her bottom clean (I keep some soap and a towel out by a spicket near the coop).
I don't know how long she's been like this but she could be dehydrated too. You can use a dropper with water and a splash of gatorade. Drip it on top of the beak because it flows around down into the mouth so she must swallow.
