Roast ducks with sage and onion stuffing

Wipe ducks inside and out with a damp cloth. Remove fat from cavity and set ducks aside.
STUFFING: Chop onions and parboil for 2 minutes, then drain. Mix with sage, breadcrumbs, butter and seasoning in a saucepan. Cook over low heat for 20 minutes, stirring occasionally. Cool slightly, then use to stuff ducks.
Truss birds with string. Prick skin thoroughly with a sharp pronged fork, and season well. Weigh ducks once stuffed to calculate cooking time. Place birds on the rack of a roasting pan. Add a little lukewarm water to pan. Cover birds loosely with foil.
Roast birds at 200 ºC for 30 minutes per 500 g plus an extra 15 minutes at end, basting at 20 minute intervals. After 90 minutes, remove trussing. Remove foil 30 minutes before end of cooking time and dust birds with flour.
To test if cooked, pierce thickest part (thighs) with a skewer. If juices run clear, birds are cooked. Skin should be very crisp.
Keep warm until required.