We got the full scoop on Costco's best convenience meal. There are many beloved Costco items warehouse shoppers swear by, but none could ever dethrone the famed rotisserie chicken. The $4.99 favorite is known for consistently moist, delicious meat, and it's the perfect starting point for endless easy meals.We've relied on this convenience dinner for over two decades, so now it's time to find out where these birds actually come from and how, thro…