It's not uncommon for hens to have reproductive issues. EYP, Salpingitis, cancer, Internal Laying, etc. are things often seen in hens. Bloat/ swelling in the abdomen can be from inflammation or fluid (Ascites) - these are associated with reproductive disorders and/or organ dysfunction.
Your hen looks uncomfortable for sure - I would work on hydrating her, give her 1 tablet Calcium for a couple of days, see if she expels a soft shelled egg or possibly lash material.
IF there's fluid in the abdomen, sometimes draining the fluid can make them more comfortable and they can breath easier - this is not a cure, it's a temporary supportive care measure. IF she's suffering from reproductive problems, then unfortunately the long term outlook is not bright.
I encourage you, if you lose her, get a necropsy performed through your state lab, this will give you a lot of information. If that's not possible, then if you can bring yourself to do it, then perform your own informal necropsy at home. Take photos of what you see and we'll try to help you. Doing one of your own, allows you to match symptoms with what you see going on and you often gain quite a bit of understanding, as well as, a great appreciation for hens.
