We have been successful previously, though its a first time with duck eggs. Don't let the broodie go too far over the time to hatch and make sure she's fed and watered. I check mine and stroke mum every day so she gets used to me. The first time, I got the date wrong and replaced the eggs with some day old chicks as I thought they were all dud. Brought them in, tested them in some tepid water and the eggs started cheeping!