Sick hen, come turning blue / purple

[fonkymc]

Hi all. I have a rescue hen who is about 2yrs old and was a pretty bad state when we got her. She once got ill where her head was sunken into her shoulders and her eyes were closed. We took her inside and she had egg shell hanging from her vent. I took what I could out, then the yolk etc followed. I got her on antibiotics and she was better immediately, and her feathers grew for the first time since i had got her. Now, 6 months later, her head is sunken again and she is all fluffed out and slow on her feet. She has been like this for a week. Today her comb is a bit blue/purple on top today (pic taken yesterday). I have her on metacam, antibiotics, and when I administered them this morning, she had a very full squishy crop and drooled them back out. I did the 'turn upside down quickly and carefully to drain the crop' and tonnes of fluid came out. I gave her the meds again. I can't feel a hard egg inside or anything around the vent. Under her wings are spotless, so no parasites as we use the DE. I also have given her live natural yoghurt. Am at a loss as what to do next. I have spoken to my vet, and she says not to disturb her by bringing her in, as she is a scared little thing and it could make her worse. She is drinking ok, but slow on eating, and she is out all day too, not hiding away in coop. Any advice welcome. What does it look like that is wrong with her? Thanks in advance.

 

[fonkymc]

Oh, she is wormed, and due next one (flubenvet) in two weeks.