Opinions please about flock dynamics

Hi all. I would love to hear about anyone's experience or thoughts about integrating a new roo, or two, into a mature flock.

I live way back in the woods, bordering hundreds of acres of protected conservation land. For more a decade we have kept a backyard flock ranging from 10-20 heirloom birds. Since we have *all* the predators, they have a spacious and completely tight coop and run (15 square foot per bird) surrounded by a very hot electric fence tuned for bear. We do let them out completely for a few hours each afternoon to roam utterly free, typically when we are loosely around gardening but not closely supervised. Many of the birds have names but we are definitely more than halfways to a homesteading attitude rather than cuddly pets, we have eaten the behavioral culls etc. They clearly live for the hours they get to free range into the yard and meadow area. We've lost birds to predators here and there and I've overall been of the mindset that it's the balanced cost for letting them have that free time.

Our current rooster is nearly 8 years old, for the last three years or so he's clearly slowed down. My experience with our younger roosters is that they do make a serious difference in patrolling, alerting for predators and giving the hens a chance to run back to the coop and hide. I've seen them make enough of a racket to get the hens away from hawks or to call me over to chase off the bobcat or fox or fisher cat.

Today we lost two hens to the dang fox and that geriatric rooster didn't even seem to make an effort.

Since I know that other backyard farmers are often trying to rehome young roosters, it occurred to me to maybe go looking for one or two that grew up together? Replace my roo? Is this a crazy idea? Would the new bachelors stop being friends with eachother due to the presence of the hens?

In the past we had always simply raised up the odd accidental male and then culled the ones that turn out to be jerks.

Thoughts?