this is my first time in having chickens. I got two, approx 20 wk old Marans and a Isa Brown, approx 16 weeks. Ethel, the Maran is picking on Rotiseri, the Isa Brown. Is there anything that I can do to stop this behavior? I am a city person so have limited space. I have a coop with a run that I move daily around the yard. Once they are in their coop for the night all is quite but once out and about she picks on Rotiseri.