For both beef and pork roast and for chicken, I start it in a hotter oven (about 375' F) till it smells "heavenly", then cover and turn oven down to around 300'F - possibly lower depending on how soon the meal is. My MIL always did her roast and chicken/turkey at about 200-225'F overnight (like for Christmas dinner). It never killed us but it made me nervous, especially when the poultry was stuffed. On the other hand, it was usually very well cooked without being overdone.