Thank you! I cannot find any avian vet in our area, but there is a vet seeing chickens. I'll try to see if I can make an appointment. If I can, I'll let her drain the fluid. Dragon has clear fluid running out of her vent though. She carries Marek's diseease, so she is very possible to have cancer. It looks like she will be the third chicken I lost to Marek's. I bought some amoxiline and tylan for pigeon. That's what I'm using now.Unfortunately we have only had short term relief from draining water belly, although we didnt get antibiotics to treat it other than penicillin. A vet may have a better alternative if you have an avian vet in your area. If she has improved some with the antibiotics you gave her than it may be viable to drain her also. It can be scary but it is surprisingly easy and certainly worth a shot to give you time to decide your next course of action. It definitely makes them more comfortable.
The color of the fluid can give a clue to the cause also, infection (internal laying) produces cloudy to yellowish fluid. Ascites from liver failure/cancers is normally pretty clear.