Egg bound? My old hen is at it again

If a chicken is going to have a problem in my flock it's ms cluck, my oldest and in many ways favorite hen. She's a rescue, three times over. Came to her last farm because she was old, then came to us from there because she broke her leg. Anyway, after she healed her leg she laid eggs for about two weeks then stopped. She's never been healthy, always thin. She has suffered from a sour crop and was treated and healed. Lately she has been laying down, not going out with the others, has a droopy tail and seems a bit off balance. I examined her and she's straining hard, her vent is partially open and her abdomen feels like there is a hard mass, as well as fluidy and swollen. She also sounds gurgly when she breaths. I thought it could be egg bound, even though she hasn't laid eggs in a very long time. I gave her a 25 minute hot bath, and had her in a wire crate over water in a bathroom with a space heater, it's very warm. I did the boiling watery thing for an hour but I don't know how long the water should be hot and how often to add more boiling water. The whole process was a bit stressful for both of us! She did seem to enjoy the sink bath and stayed there pretty much by herself. Any help would be great! Love this girl!