I've been doing lots of reading trying to help you out. I hope you've been reading too. There is a wealth of information of here. I kept coming up with Blackhead the more I researched the yellow poo. It's more common in turkeys and rare in chickens, but it happens.
Read this very good thread...and search more on Blackhead. If you have Cayenne Pepper on hand you could try mixing it into scrambled eggs and feeding it to her. It can't hurt!