New Chicken Owner Questions

[kip5254]

Hi guys!
So I've had four two-year-old chickens for about two weeks now and just have some general questions about their looks/behaviors. All four are red sex-link hens.
Okay, so the first thing I've noticed/questions is some missing feathers on only one hen's lower neck/upper breast region. The fluffy part of the feathers are gone but the quills where they were attached remain and are visible. We received her like this and it does not seem as if she continues to lose many, if any, more feathers. What could have caused this and do I need to worry/remedy the situation in any way?
Also, this same hen (Lulu I call her) is the nosiest of the bunch. Mostly the girls are very quiet except she who like to cackle and make a caaawww-caw-caw-caw type of noise a couple times a day. Any ideas what she would be so noisy about? Just general chicken noises? At first I noticed she only did it when inside the run so I assumed it meant she wanted to be left outside, but she's also started to make the noise when outside.
Alright, I think that's all the questions for now.
Thanks!
Katie

 

[rIrs roost]

If its missing feathers on the lower back it could be from a rooster mating. If its the chest area she could be broody. Or missing feathers could also be because of molting. The noises could be because she's layed or fixing to lay. But it could be that she's just a talkative hen. If their acting fine eating and drinking, I think there's nothing to worry about.