I don't know what is wrong with my chicken but something is not right. I've done a lot of research on here but I still can't figure it out. For the past month she has been becoming more isolated from my other hen and is very lethargic. She sits by herself all day and always sits next to a tree, wall, or fence. She used to come running up to us when we went outside but not anymore. She has been molting for over a month now and has not layed an egg in over a month either. She is eating and drinking normally and her poop seems okay. She experienced a case of fly strike about 6 months ago. We caught it very quickly and she survived it but I am not sure if that has anything to do with it. Maybe she was traumatized? I started her yesterday on Cephalexin 250 mg/ 2 times a day. I have also tried feeding her a yogurt mixture with vitamin B complex, vitamin E, and Selenium added in it but she didn't really like it. Is there something from the pet store I can buy to give her? Any advice would be greatly appreciated. I am getting really worried! My husband said when he went out this morning her neck was laying completely back (like it was broken) and it seemed like she couldn't move it for a minute but then he picked her up and she was fine again. I though it might be Marek's at first but it seems like that is more common in chicks. My hen is around 2 years old. Also it seems that chickens with Marek's can barely walk she is able to walk it's just very slow.