I was going to ask this question, and i see thatyou have answered it, thank you.
To the op, good luck with your girl! What an amazing chicken parent you are to be doing whatever you can to try to help her.
Did this end up being a pullet? I have some 6 week old blue orps and i have one who looks just like this. Looks like a pullet, but very slow feathering. I am keeping my fingers crossed! :)