Choosing a new rooster

I recently culled my rooster due to bad behavior. I'm left with 11 hens. 3 older birds and 9 year-old birds. I'm wondering if I should introduce an older or younger(year old) roo or maybe go with a baby raised at home(we have a hen that goes broody and hatches out a batch every year).

 

I'm aware that I need fertile eggs to hatch babies(I have access to fertile eggs) and in previous years I gave her day old foster babies to raise( which btw worked like a charm) so that end is covered. My concern is a young roo may have trouble gaining control of dominant hens. My previous roo took to viciously beating my favorite hen on account of that. It got so bad(even after it appeared she was submitting) that he was drawing blood and it looked like he was trying to kick her out of the flock. He also did this to a sickly hen and since he seemed to have this bully, "I rule or your dead and no one gets to be sick around here" complex I culled him....this isn't Harlem, it's peaceful sunny horburg! So now my girls need a new man. Hence the question...old or young? and how can you tell if they will be a good flock master(or can you?) . I've had several Roos over the years but this was the first bully(incidentally he was an Americana hatched on the farm and took over as head cheese when the other old boy passed).