Twitching Butt?

[bblynn_chicken]

Went to check on my chickens one last time for the day, and found my 4 pullets up in the roost, as they usually are at this time. Went to check for any possible eggs from one of them who has laid three (Sunny, ISA Brown), and noticed that my Barred Plymouth Rock Henrietta was acting highly unusual. She kept twitching her butt and was messing (not picking) with her tail feathers and bottom. Could she be about to lay? Or is there something else?

 

[Brahma Chicken5000]

She might have been preening which is normal chicken behavior.

 

[Folly's place]

Or she's got lice or mites? Go out with a flashlight and check at skin level for them! Check several birds, because one may have many, and the others nearly none.
Mary

 

[bblynn_chicken]

I checked for mites, there are none. I think she was just preening. Thank you, guys!