I have heard of this before, but never experienced it. I saw one of our young hens on the front porch. She flapped her wings, shook herself, and extended her neck. I then heard a crow I had never heard before coming from where she was. I was so astounded I went and looked out the door, everywhere! No roo in sight. It had to be her! We have several roos, so i'm sure she's used to that form of communication!