Mites/lice?

[Chicks Galore3]

One of my chickens, (BO, dandelion.) looks like she might have mites/lice.I checked to see, but I couldn't find anything. But I don't know exactly what I am looking for. Her butt fluff looks like it has been "chewed." There is just the very bottom of the feather. She MIGHT be walking funny. I'm not for sure. She's eating, drinking, pooping, and egg laying.

 

[BuffOrpington88]

If you look at the base of the feathers, it will look like dirt is clinging to them. There are some great article on the web on identifying mites and lice.