Hen preoccupied with pecking at claws?

[elisec]

A seemingly healthy hen (I checked her for mites, etc.) started to become obsessed with pecking at her claws; both lifting her feet up and pecking and while standing. Any ideas?

 

[Eggcessive]

Can you post a close-up picture of her legs and feet. Scaly leg mites could be a possibility.

 

[dawg53]

Does she have long claws? Does she have caked dirt between the joints?