poorly chicken?

first of all verm-x will not get rid of worms - you need to buy flubenvet which is proven to eradicate worms.
Wash her rear and then use something like germaloids push her protrusion back in. then you need to stop her laying so bring her in and keep her calm and in the dark. sometimes hens can recover from a prolapse which it sounds like your girl has got but she will need careful supervision and maybe regular treatment.

ok she needs to see a vet urgently - the yellow colour could be a yolk (also why her feathers are sticky) - it sounds like she has had an egg break inside her - possibly a soft shelled or shell-less one (hence the possible prolapse caused by trying to push it out). She will need some antibiotics to stop any infection and also a check over to see if any is still inside her.

I have just spoken to my vet who knows about chickens and he says while she is eating, drinking and generally looking well I should just keep an eye on her, I have just thrown out some pasta and corn and she is tucking in with the rest of them. Will let you know how she gets on.....