Help I think my hen has water belly

[Belovedturkey]

I think my bufforpington has water belly, I noticed two days ago that she was having neon green watery poops and that she was bloated, but I couldn’t feel a stuck egg and her crop was emptying fine. Last night she wouldn’t Roost and she’s really lethargic this morning. She went down hill really fast and I’m not sure if I should drain her or be more sure that it’s water belly first. I soaked her and trimmed the feathers around her Vent because they’re starting to collect poo. I’ve also noticed that other birds have been picking on her and pecking her comb. Her sister died of water belly a couple years ago. What should I do going forward? You can kind of tell she’s bloated in the photo and I did clean the poo off her after the photo was taken.