It is best to thaw the duck in the refrigerator. It takes about 24-48 hours to thaw a whole 4-6 lb. duck. Do not thaw the duck on your kitchen counter.
To thaw in cold water, immerse the duck in its original packaging or in a watertight bag and change the water every 30 minutes. A 4-6 lb. duck will thaw in about 2 hours.