Saw it with my own eyes!  I thought he was tussling with one of the young roos, but then these 5 foot wings opened up, and I realized it was a hawk!!  I sicked the dogs out on them, and my SO were right behind them!  Fortunately the two young roos had already hopped into the fray, and with the dogs charging towards them, the hawk decided to retreat!  Chester appeared unharmed, but did limp for a day or two, but mostly it was all the poor hens stuffed into the wood pile, under pallets, and into PVC pipes that we had to find and get unstuck!  Poor things!
But that is what Roosters do, I have seen Chester charge at several hawks, while alerting the world!  I would never consider free ranging a flock without a couple good roosters around!