Help please? About 3 days ago one of my chickens laid down and hasn't gotten up. She hasn't laid any eggs and is barely eating. When I go near her she make a high- pitched sound and her feathers stand up. She stood up once today when I was hand feeding her boiled corn but she laid right back down. She's about 7 months old and I only brought her a month ago. What might be wrong with her? What do I do?