My husband brought home two ducklings today that I'm pretty sure are brother and sister. They look nearly identical. I've heard that the eggs would be fine, but that just doesn't seem right to me. If we bought another female, would the male know to only mate with that one? My guess would be no, but figured I'd ask people who know more than I do. Would it be better if we just found a home for one of them and replaced it with one who wasn't related?