I thought they were friends

[Chickemee]

At first I had my 3 little chickens together and then the little roo got sick. Then it was just the little mutt chicken and my buff orp. They were doing great together until today, my litle mutt was beating up on the little orp so I had to seperate them for a little while. They're together right now but why has my little mutt become so mean?

 

[Josie]

I have heard that every time you take away or add birds to the flock, they need to rework out the pecking order. Try to monitor the situation, and it should mellow out again in a while. (Though it may restart when you reintroduce the roo!)