Baytril is a good antibiotic for birds and should help with any infection. I don't think her temperature is that much out of normal. My birds seem to run 103-105 however, if she has an infection, 108 seems to back that up. I do think its important to get the fluid out of her....you don't have...
Good luck with your hen. It's obvious you care for her.
My hen eventually passed away from the effects of anesthesia following surgery for a blocked oviduct. Her normally squishy abdomen started getting hard and an xray showed a mass in her oviduct which turned out to be a blockage that...
It does sound like ascites. I had a hen who survived with it for several years. It can be caused by congestive heart failure or fatty liver disease (the case with my hen). I took her to the vet about every six to eight months to be drained and she perked right up afterwards. The fluid, if...