Molting?

[millcjsao]

What is happening here and what do I need to do about this? This is her lower back and we don’t have a rooster. Thanks!

 

[Rldad1]

If she is loosing other feathers, she is probably molting. Some chickens can go almost as bald as me.

 

[Wyorp Rock]

What is happening here and what do I need to do about this? This is her lower back and we don’t have a rooster. Thanks!

Looks like she's being plucked.
How much space do you have in your coop/run? Photos?
How many birds? Photos of the flock may be helpful as well.

Observe the flock's behavior especially during roosting, this may be when you see her getting plucked.

Pine tar on the bare back may help deter picking and help the skin to heal. She's got some breaking down of tissue there that needs to be watched.