I have a muscovy (mama) mallard (daddy) cross which I know makes her infertile. She lays tiny eggs, and she was so vicious the first time she went broody that I let her sit for a week until I was was sure that the eggs were not going to be viable. I found another nest of 13 eggs in a horse stall when she started sitting over 2 months ago (she started laying again the next day). I slowly began removing her eggs until she was down to about 5 eggs. I decided to let mother nature take her course and allowed her to continue sitting. On day 45, I removed all of the eggs. She continued to sit. After another 10 days, I disassembled her nest and walked her to the pond where her mama and multiple siblings hang out. She beat me back to the barn. She sat an empty nest for 17 days, so finally, on day 62, I gave her 2 chicken eggs to sit just out of shear desperation. IF these eggs should hatch, I'll be hand raising 2 baby chicks through the winter, and my luck they will be roos. How in the world do you break a broody duck that is obviously prepared to spend the rest of her days sitting on an empty nest??