Here is a nice funny story for you all.
I have roosters and can easily tell them from my hens when they are mature, most times when they are 2 months old or even less on the tall comb breeds. But the same is no where near true for my ducks apparently.
I thought I noticed a fertile egg here and there from the duck pen for the last two weeks. But I thought it was me and I was just seeing things. But today I mad scrambled eggs from the last 4 days of duck eggs. They were all clearly fertil. I still haven't a clue which of our ducks is a male. I have not seen a single duck getting mated for months. And roosters while they will mate a duck don't produce fertile duck eggs.
uh oh... And to think I got two hens from you....hmm lol