My 2 cents: I’ve had an "open air" compost heap like Margaret describes for 20+ years. I have never, ever had a rodent or odor problem. In fact, I keep a small "pile" (in an old crock pot) in my kitchen (sometimes for three or four days) to collect cooking scraps, etc. before heading out to the compost pile, and it never smells either. IMHO, if you never ever put animal matter in your compost, you will never ever have an unpleasant odor. Animal matter would include dairy products as well as meats, animal fats, etc. Anything vegetable will decompose without odor.