I checked on the "ducken" thing & from what I saw it isn't a real animal. Are you sure someone isn't sending you on a snipe hunt here...
As for the chicken eggs, have you candled them...(sorry, some of my keys aren't working) If you have & still see movement then let them keep going. They may still have a chance if your temps have been running low. As for the ducks, they require a bit higher humidity for hatch than the chicks, so your chicks are in more danger than the ducks if you get the humidity up for the ducks.