If you are talking wild duck eggs, I would suggest you consider them a loss and put them back.
I know what your heart wants to do, but I am not sure you want your pocketbook to take the hit that will occur if you get caught with a wild duck. I believe you need a state game farm license and federal waterfowl permits to even have them.
I would not contact the warden, I would just put the eggs back and let the skunk or whatever have them. I am not saying this because of my extreme dislike of waterfowl, I am saying this out of concern for you and the legal problems that could ensue if you hatch them. I believe just possessing the eggs can be a hefty fine.
If you tell the game warden you have the eggs I don't think they'll fine you because you told them. I once told them I had a young Robin with a hurt leg, I wanted them to take it and fix it, they suggested I put it down.