We have three ducks, two girls & a boy, all three hatched in May. Last Tuesday we discovered our first egg. We had another one on Wednesday & then another one on Thursday. Nothing Friday through this morning or so I thought. I was just in their enclosure with them when I decided to look a little closer to see if maybe I missed an egg this morning & this is what I found hiding in the straw...four eggs! How do I know if they’re fertile? We are new to having ducks so we have lots of questions.