I give mine mash on the liquidy side and top it with meal worms and a dab of yogurt to entice her to eat when she is having any problems and it usually works.
I'm sorry this is happening to your hen. I have had one of mine act like this who laid only a yolk. If I wasn't there right after the other chickens would of ate all of it. She then developed an infection which we treated with an antibiotic. Separating her really helped and feeding scrambled...