She looks like she is molting or has been severely feather picked. She may be ending her egg laying days, or if molting will stop temporarily. I would give her some human calcium citrate with vitamin D 300-600 mg daily for about 7 days. You can find that at Walmart or other pharmacies. Are you feeding her a layer or all flock feed and offering crushed oyster shell for calcium? If her egg shells don’t improve, she could be suffering from a reproductive disorder. I would offer some extra protein in her diet to help with feather growth. Egg, rinsed tuna or salmon are good.