8 month old Golden Buff Rooster picking on 4 month old RIR Cockerel

[cntrywmnkw]

My neighbor gave me a beautiful 8-9 month old Golden Buff rooster that was at the bottom of the pecking order at his place. I have a 4 month old RIR cockerel that was "supposed" to be a pullet, but surprise, she turned out to be a he, anyway, now the "NEW" older rooster is chasing & picking on the little one. I have 3 laying hens & 8 4 month old pullets. My questions are:

1. Should I separate the boys or let them work out their differences?
2. Should I be concerned that the younger one is a RIR, who have reputations for being aggressive or should I just wait & see if he becomes aggressive?

Thanks in advance for any advice you may have.