We have 3 Peking ducks that are about 7 months old. My daughter opened the coop yesterday and there were 8 eggs. These are the first eggs we have seen. I thought they would be big, but they are about the size of chicken eggs. We have not figured out of our ducks are male or female. How do we know if the eggs are fertile? And on another subject, how do they do in the winter? We have an indoor shed for them where we put them to bed at night to keep them safe, and an enclosure for the daytime. Will they go out in the snow?(We live in Illinois). Do we need a heat source? We are new to the duck world, so any information is appreciated.