I'm still relatively new to being a chicken keeper. I have had a mere two flocks under my watch, one which I have recently relocated to a friends property. My second flock is comprised of 8 hens, two of them being Rhode Island Reds, 4 Barred Plymouth Rocks and 2 Columbian rocks. They're just reaching reproductive maturity, laying small eggs a little sporadically. I have just acquired an Australorp rooster of a similar age, maybe 3 weeks younger. I've tried a slow introduction into the flock and for the most part it seems to have been successful. All Barred Rocks, as well as the Rhode Island Reds, seem to have accepted him. However, with that being said, the two Columbian Rocks are giving him a hard time, actively seeking him out to peck at him and chase him around. This doesn't really come as a surprise to me, taking into account that they were definately the dominant birds in the flock before the introduction of the roo. I was just wondering if there's anything I can do to ease the situation, I feel bad for the poor fella, they've got him running scared eventhough he's twice their size, and I'm a little concerned they may injure him.