One of my chickens is losing feathers around her neck. She is a Dark Brahma and is 10 months old. She started laying early at just a few days past 5 months and I have heard that early layers sometimes molt early. These are my first chickens so I'm not familiar with molting or really anything yet. She doesn't behave as if she is ill and the other chickens (a total of 4) are not showing any of the same symptoms. We have been getting a lot of rain lately and at first I thought she had gotten her feather wet, but now I'm realizing that they are really thinned out. They have plenty of dry places to be, so she is able to get out of the damp. How do you know if they are molting or have a parasite of some kind?