Pullet with swollen, soft crop

[Dewclaw83]

Yesterday morning I noticed my barred rock pullet had a distended crop that was soft to the touch. She was rather sluggish and uninterested in food. I didn't have much time yesterday, but this morning the cropped looks slightly flatter, though she was a tad more listless. When I moved the other pullets to a different pen, she hardly cared that she was left alone. She feels a little lighter than usual as well.
Looking online, I'm thinking maybe she has sour crop? The source I found recommended isolating her without food or water for ~12 hours, and massaging the crop top to bottom every few hours. I've started this process, but I thought I'd check here as well.

These pictures were from yesterday morning.
Her comb looks a little paler today as well.

 

[Eggcessive]

How do her poops look? Does she have a sour odor from her crop? Hens who are sickor even broody may have a slowed down crop, but if her crop does not empty overnight, I would start suspecting sour crop. How old is she? Here is an article about crop problems:
https://www.backyardchickens.com/ar...w-to-know-which-one-youre-dealing-with.73607/