What's wrong with my hen?

Hello, one of my 26 weekish ladies was diagnosed with sour crop on Friday. The vet flushed out her crop and she seemed to be halfway back to her normal self. On Saturday she drank ok and took some bio youghurt but didn't really bother with her food (I'm assuming she's lost her appetite or her throat is sore from the vets). Saturday evening, on the advice of some other hen keepers, I infused some extra virgin olive oil with oregano (hoping to give her some calories) and she again very willingly took this. However this morning she seems to have gone down hill again...

When I went down to their house this morning my other two girls were already out, but Michelle was just stood in the doorway. When I went to have a look at her her vent feathers are covered in a pasty yellow substance (much lighter than egg yolk but what else can it be?) Also she was stood with her beak open and I could literally hear her breathing! I left her in a sheltered spot with food and water while we went out and literally 6 hours later she'd only moved a foot. Her droppings were quite liquidy with a small amount of normal coloured waste and this yellow stuff. However she did take a little yoghurt with a small amount of Daktarin mixed in.

I've now brought her into the kitchen in a cage where I can monitor her better, She's had quite a bit to drink  (self) and I've offered her some softened pellets which she's not bothered with. She just seems to stand there with here head and tail down and her eyes closing....

Any ideas anyone? 

Thank you. I'm pretty sure it's egg as she's displaying all the signs of egg peritonitis or at the very best trying to pass a shell-less or soft shelled egg. Hopefully it won't be too late 

Any news Mrs S?