Help sour crop or what?

[Aimee2013]

My hen has been off colour, I think she had sour crop when I first drained her the liquid was see through, the next day it was red and stunk and then it went yellow, now the liquid is yellow with brown lumps in. I have no idea what to do I have been feeding her natural yoguart with a egg beaten into it. Today I mixed it into layers pellets! She has got the colour back into her comb but I don't know what to do her crop was undetectable where it was empty and now it's just full of this yellow liquid!