Well I had a roo I wasnt sure about, he seemed protective of his ladies, etc but he was a pain growing up. He turned into a fine protective guy and would call the girls to eat, etc before he did, but it was hard for him, he was a pain growing up by stealing all their food and eating first, etc, so I wasnt sure how he would turn out. Still he was only 5 to 6 months old when the attack happened, no spurs or anything, poor guy.
He turned out to be a wonderful roo, we had two dog attacks. The first dog attack, (I wasnt home but the handyman was), the roo fought and engaged the dog about 15 times trying to save "his" girl/s.
He saved all the girls but the initial one, which was his favorite lil silkie hen...but he died in my arms later that eve. He was valiant to the very end and I think he died more thinking he failed his girls than anything.
The dog came back three days later and without my roo to give them all time to hide, the dog took out 12 more of my flock.
I had a small young silkie roo with some of the hens, but he ran and hid, letting all his girls get slaughtered. He was the only survivor that was out that day.
So it just depends on the roo, I suppose. I know without my huge orp roo, I would have probably lost my whole flock the very first day. He really gave them time to hide while he gave his life for those precious seconds.