The average cost of a gallon of milk nationwide has gone up almost a dollar since 2020. “CBS Mornings” co-host Tony Dokoupil goes up the supply chain – starting from a grocery store, to a farm, to an animal feed store – to track down where inflation really begins.See Privacy Policy at https://art19.com/privacy and California Privacy Notice at https://art19.com/privacy#do-not-sell-my-info.