Are you considering turning your backyard into an urban farm? Or perhaps you’re considering a back-to-nature relocation to the country. We’ll discuss trading the rat race for chickens, goats, bushels of produce and lots of work this hour with Josh Kilmer-Purcell, author of “The Bucolic Plague: How Two Manhattanites Became Gentlemen Farmers: An Unconventional Memoir” (Harper Perennial, Paperback, 2011).