It looks to me like a partial block of her crop; probably your hen ate some sort of fiber (grass, hay, or something else long and thin) that coiled into her crop and is now keeping the food from fully passing through to the stomach. I suspect something similar in one of my own hens, but at the same time her crop also seems to swing on top of looking unusually big at dusk, so I'm thinking she might have developed a pendulous crop from partial food blockage in said crop. My hen's been drinking alot of water and having watery poop ever since I've had her mid-december.
Form what I've gleaned on the subject, isolating your hen with no food, just water, for a day, helps her crop digest the excess food. Adding a bit of food mixed with alot of grit the second day helps crunch the food even more. Massing her crop 3-4 times a day also helps. Giving her oil does the same, though dosage is needed. Lastly, if you hen is suffering from a pendulous crop, which is damage to the muscle that supports the crop, the best thing to help your hen digest well again on top of grit in her food, is to give her a crop bra - attach a makeshift or cuztomised bra under her crop so it can raise the sack and stop it from hanging and trapping food inside it. Stopping the crop from hanging like a pendulum should help food pass more easily into the stomach. (link here for more info on the pendulous crop:
https://www.backyardchickens.com/threads/huge-pendulous-crop-video.1229417/)
To cover more ends, you might want to check for parasites in a fecal (float?) test. There are some who give the hen a slow crop, and one particular parasite can even inhabit it (I think it's called the crop parasite?) and cause mayhem in there. Getting a fecal test done will tell you whether it's parasites, bacteria or something more, like a possible blockage of the crop caused by a tangled net of fibers in there. Do the nest boxes of your hens have hay? That can be one (if not the) cause of your hen's crop problem if she's someone who likes eating long blades of grass during summetime. Mine has been doing it since day one, so I have a strong reason to suspect she's landed herself in trouble with the hay from her nestbox. I've changed the hay for wood chips last week, just to be safe.