I had a problem at first when I added my 4 new (2 EE's and 2 Brahma) My Production Reds were bent on killing them, particularly the Brahma rooster. Luckily though the 4 newbies were picked up on the same day so they all bonded quickly and so as the Brahma rooster quickly outsized the bully RIR and got his rooster mojo he has knocked the Reds down considerably. I am almost sad to see my Reds that used to be so confident and pushy are now submissive and almost reclusive but it means that the EE's are relatively safe because they hang out under the shadow of the rooster all day as the older girls hide from him by hanging out on top of a compost pile that he cannot easily navigate due to him being a bit of a klutz. Though he is really a sweetheart of a guy he is a little too randy for the older girls liking but the EE's benefit from his tactics haha.
My friend's red sexlinks were a bit pushy and she had to separate the 3 into their own pen. I consider sexlinks along the lines of heritage/dual purpose breeds -- assertive to downright bullies. It's good you have a roo to keep the hens in line. Aggressive hens need to be supervised by a roo. The gentle flock of girls I have now are quite peaceable and don't need supervising - 2 Silkies, an Ameraucana, and a Breda. I can leave them free-range for the day and come home knowing I won't find any that have been in a bloody fight. What a difference since we re-homed all our popular dual purpose LFs. We get less or smaller eggs but there's way less stress for me now.