I have 8 chickens that are about 3.5 months old. One of my chickens we call Tiny was seen today with all the feathers on the back of her neck and head standing up. She seemed to be doing it at our rooster, and then she laid down in front if him. She did that twice and then he ended up walking away. I saw her do this a few days go too, but my dog was the only one around that I know of. I haven't seen any if the other girls do this. What is she doing? Isn't she too young to be trying to mate?