Chicken with ruffled feathers

[Wendykneil]

I have a lovely little flock of 5 girls that i got as chicks 10 months ago. I noticed today that one of my gals, Speedo, has some ruffled feathers around her neck. Is this molting or is she being picked on? All the others are all looking great. If she is being picked on what do I do? Cold winter has kept them in their coop more than not so maybe that is a factor? or Diet? This is my first winter with chickens so any advice would be great. Thanks!
Wendy

 

[nuthatched]

Can you see pin feathers coming in?

 

[rosemarythyme]

Photos would help.