>So what, then, has prevented new startup chicken ranchers from popping up all over the US to capitalize on the overpricing?
Capitalism. Which is less about "free trade" and disruption, and more about big players securing any niche for themselves as best as they can (government regulations not required for that either -- they can also do it with buying out smaller competitors to prevent disruption, dividing the market between themselves and forging cartels, playing retailers against one another and taking advantage of their economies of scale, undercutting on price while smaller competitors die and then jacking it, etc).
Capitalism. Which is less about "free trade" and disruption, and more about big players securing any niche for themselves as best as they can (government regulations not required for that either -- they can also do it with buying out smaller competitors to prevent disruption, dividing the market between themselves and forging cartels, playing retailers against one another and taking advantage of their economies of scale, undercutting on price while smaller competitors die and then jacking it, etc).