Is there any holiday food more fraught than the turkey? First it hogs the refrigerator, and then it hogs the oven. Never mind the logistics of thawing, seasoning, and roasting. After all that, it often turns out dry and bland. A well-tested recipe and the right equipment go a long way toward a better bird, but there’s another variable: The turkey itself matters just as much. To find the best supermarket bird, we purchased eight best-selling turkeys from both national and regional brands.