There are varying opinions about cooking the turkey breast side up or breast side down. The former achieves a golden brown skin, the latter reduces the chances of the breast meat drying out. Some say to do both, flipping the bird halfway through to brown the skin. If yours is a very large bird, it may get tricky flipping the turkey halfway through in order to brown the skin. Using an oven bag eliminates the debate as it keeps the turkey tender while also browning the skin.