I have 4 Roos, a B Jersey Giant, Lavender Orpington, Buckeye, and Midnight Majesty Marans. My Buckeye is a sweet lovable guy he is not confrontational at all so probably not my best protector. My lavender Orpington is a Gentle Giant, by far the largest of my Roos and at the top of my pecking order, only because of his size. He is mellow don't know how he would react to a predator. My black Jersey Giant and Midnight Majesty Marans are in the middle of the pecking order and look to be equals, My JG has never been aggressive with people but doesn't like to be held, my Midnight Majesty Marans got aggressive with me 2 times when he was a juvenile, I did not let him get the upper hand I turned on him and picked him up and carried him around the first time the second time I chased him down. I have never had a problem with him since. He is the best protector I have in my flock, he is always looking out for his girls and if he hears one making a fuss he is the first to investigate. He has turned into a fine Roo who I know would protect his girls to the death if need be. Having said that all my Rooster breed the hens some a tad bit gentler than others but any hen will get tattered if any Rooster breeds her too much, and Roosters have their favorites. I'm going to separate my Roos from my hens for a while so they can take a breather. You should have at least 10 hens to most Roosters, extremely aggressive breeds around 15.
Here are some pics of my roos. My MMM and BJG lost part of their comb last winter.