strangest behavior in my hen

[peep this]

One of our 20 week old hens has been grabbing clumps of dry grass and tossing it on her back. Has anyone seen this before? She was also laying pretty much every other day, but lately she has taken a vacation of 3 or 4 days. Should we be worried?
Thanks

 

[sourland]

A lot of hens will do this after laying an egg and just as they leave the nest. Almost seems like an ingrained trait from when they had to cover the nest as protection from predators. Nothing to worry about. She may be getting ready to go broody.