We have lost chickens to eagles, hawks, owls, coyotes, and bobcats, but never a buzzard; that I know of. The smaller ones are going to be the natural first choice of predators. Free ranging is going to be more opportunistic to predators than a net covered pen. A good scoped .223 and a little diligence will slow the problem, a Rooster will NOT. We have a huge Red Leghorn and he rules the roost, but no help in an air attack of snatch and grab. Multiple roosters will result in 1 head rooster and subordinate roosters or none.
Too late. My son is checking with his friends whose step dads have game cocks. I want to put a combat veteran in there...