With found curbside logs from downed trees, leaves, twigs, cardboard boxes, and a little charcoal to get it started, I was able to cook an 11 pound turkey and 10 pounds of chicken outside in my
cast iron lidded pot. I found it cooked better after I added rocks up around the pot to keep the heat in(not shown in picture). I made this fire pit with chunks of found concrete and an old oven rack. The bottom is lined with pebbles and smaller concrete chunks.
It took many hours, but while it cooked I was able to clean up and compost all those leaves! ; ) The fresh air and sunshine was nice too.
The turkey turned out moist and delicious! If you have a day to do this, it's fun and produces a great result. You can't leave this like a crock pot and come back. The fire and food must be tended and watched the entire time. It certainly makes me appreciate the labor that goes into cooking on an outdoor fire for a family.
A more efficient and environmentally friendly option would be a rocket stove which maximizes combustion requiring very little fuel.
This one is portable, but
you can build one too with 16 bricks. Rocket stoves burn without smoke which makes them better for maintaining air quality. That's a project for another day.