If you are not getting fluid out with repeated sticks, there might not be fluid, but solid material or thick secretions from egg yolk peritonitis. Fluid should not be foul smelling unless there is infection.
Here is some reading about persistent or cystic right oviduct in chickens:
https://www.merckvetmanual.com/poultry/disorders-of-the-reproductive-system/cystic-right-oviduct-in-poultry
https://www.thepoultrysite.com/publications/diseases-of-poultry/221/malformations
@casportpony has done a lot of draining of hens abdomens. What color is the fluid that you have drained before? It should be yellow to dark amber in color. If it is clear and colorless, that can be from a cystic right oviduct, not ascites fluid.
I have only drained one small bantam hen of mine...