Rinse the ducks with cold water and pat them dry with paper towels. Place them in a large shallow dish or plastic container and refrigerate, uncovered, overnight.
Preheat the oven to 500 degrees.
Place the duck, breast side up, on racks in several shallow roasting pans. Prick the skin all over, especially along the side of the breast, so that the fat can run off while roasting.
Roast for 20 minutes, then reduce the oven temperature to 350 degrees. Continue roasting for 15 to 20 minutes per pound. Begin to baste with the glaze once the ducks have been roasting for 50 minutes. Baste every 5 to 10 minutes. The ducks are done when a meat thermometer registers 170 degrees. If you prefer your meat well done, continue to roast about another 15 minutes, but be aware the meat may become a bit dry. Discard all but 1/4 cup of the residual fat in the roasting pan, reserving for Apricot-Orange Duck Sauce recipe.
Cooks Note: Unless you have 2 ovens, roast 3 ducks at a time. Reheat the first set of ducks for about 10 minutes, or until heated through.
Place one of the roasting pans, which have been drained of fat, on stovetop. Set heat of burners to medium, add the 1/4-cup fat and stir to loosen pieces from bottom of pan. Whisk in stock. Simmer for 15 minutes, uncovered. Add apricot-orange glaze; simmer 5 minutes.
Meanwhile, place flour in a medium bowl and whisk in 1 1/2 cups liquid scooped up from the pan; blend well. Add flour mixture to pan, whisking until well blended. Simmer 5 to 10 minutes or until slightly thickened. Add salt and pepper, to taste.
In a large bowl, combine all the ingredients and mix well.;