I Never cover in Foil.
I immerse and soak it in water for 48 hrs with maple syrup, a bouquet garni, peppercorns and sage. Then cook it very slowly at a low heat(90 deg) for about 4/5 hours and half an hour a little higher an hour before you need it. Then let it rest and cover it only whilst resting. Use a baster at this stage to inject the bird with its juices under the skin - don't just put the basting juice onto the skin as it will just run off. Always use a meat thermometer to test the bird at different points around the body.