Is 10 months too young for molt?
More than likely, another chicken is pulling out her feathers. Many lower pecking order chickens will just stand their and let them do this. I have watched a few do this to their neighbor on the roost before bedtime. Look for any evidence of lice or mites on her skin and especially under the vent area. Make sure your chickens are eating at least 16-20% protein in their food, and limit low protein snacks. If they don't have enough room or are kept inside during the day, they will peck each other out of boredom. Putting a bad tasting cream such as Nustock on her skin may keep them from pecking her. When the new feathers start to grow in, they are more enticing, so I use BluKote spray to hide the bare skin.
Our 9 mo olds (at the time) started a mild molt in October, finished in late Dec and started laying again at the beginning of January. It looked like a feather pillow exploded in the coop & run yet no one was naked or wounded lol.
Edited by Becky388 - 2/3/16 at 2:21pm