Sometimes the nekkid patch at the base of the tail is from an overly enthusiastic rooster. Do your girls have a rooster in with them? An apron (a fabric coat of sorts) will help keep the rooster from breaking off their feathers.
Mine are all molting also and look pretty pitiful. I'm ready for everyone to grow in and be done with it!
I have no rooster. She is naked on her neck, has been for a while and now whole feathers are just falling out as she walks from everywhere. Is that how they molt? I didn't see it last year. must be the age?
Chickens will generally molt starting around the neck and progressing to the back although its not a linear progression. If she is only losing feathers at the tail, I agree it could be a rooster or another hen pecking at her. First molts usually happen around 12-15 months and while she's molting, she won't be laying. If she's still laying eggs, I would suspect someone is picking on her.
Is there any redness on her skin that might indicate the feathers were plucked versus just falling out due to a molt? If not, it sounds like a molt, especially with the missing feathers around her neck....however, she should stop laying..if not now, then very soon.