Slowing down fast growing chicken to improve bird health and get better flavor

We raised two very different flocks of chicken this year. Both were raised on pasture in our chicken tractors, both were given organic feed to supplement that lush pasture, and both were the same breed from the same hatchery, the famously fast-growing Jumbo Cornish rock breed that makes the news a lot these days.  Everything we did was the same for each flock except for one thing: how much time they had access to food every day.