My hen Flick, an amerucana, is about 6 months old. I have had her since she was 4 days old. After her coop mate Richie died we got two new chickens. Dot, a Wyandotte, is about 5 months old, and Daisy, a lavender amerucana is about 4 months old. Recently Flick and Daisy have started to gang up on Dot and last week we rushed her to the vet because the back of her head was torn open. We thought that Richie got attacked by one of our dogs, but now we are not sure because she had a similar injury to Dot, only it was severe enough to have to be euthanized. Fortunately Dot survived and only needed some stiches. We have her inside the house while she recovers. Flick is laying eggs and now and seems to be extremely aggressive towards Dot only, she leaves Daisy alone. We also believe that Daisy may be a rooster because she has been crowing, she has a long neck, and her comb is bigger and darker. Also when I pick up Flick she makes a blood curdling screech. She seems depressed, or just angry all the time. Will our chickens ever get along? Is there anything that I can do to help the situation? Is Flick a serial killer?