Our five week black sex link is loosing a couple neck feathers a day. This is not happening to any of the other chicks. I have one chick which I think is a rooster though "he" is not crowing yet. I clean the coop out weekly, rake the chicken run and spread DE in both coop and run. Any suggestions? Also, is there anything you are doing with your chicks besides what I've mentioned? They are eating the medicated feed. Thank you for your suggestions and answers.