What do you mean by "treat her with diatomaceous earth"? What are you treating her for? DE doesn't treat anything. It can help with exoskeleton parasites, but that's about it.
How old is your pullet?
When did you notice a problem?
Have you dewormed her?
Is she inside so you can keep an eye on her?
Have you tried feeding her or giving her some vitamin water using a syringe or dropper?
Is her crop hard, soft, normal, flat, distended?
How are her eyes.. bright, dull, pupil odd shaped?
These are things folks will need to know in order to help guide you with some solutions to try to save your bird. I wish you all the best!