What did you use for worming? Normally if using Valbazen, repeat the wormer in 10 days. That gets the newly hatched eggs. With SafeGuard either worm for 5 straight days for most worms, and worm once and again in 10 days to get just roundworms.
Get some plain greek yogurt. They even sell small cups of it for a dollar. It has more cultures and probiotics, and less flavoring and sugar which the flavored sweet yogurts have. Vanilla yogurt has very little actual yogurt in it, with all of the sugar and flavoring.
I would withhold feed with an impacted crop, but with a sour crop I would feed mushy feed with a lot of water, and give something for a fungal infection. I am not a good authority on crop problems. Mine who had them did not survive because they were due to a reproductive issue or something else...
It does sound like she may have early sour crop. Crop problems accompany reproductive disorders in hens over two, and they can also have other problems. Here are some articles about crop problems that are helpful...