I have used this method a lot in the past and it's been dead on. I was just wondering if it's possible to sex a 3 week old ducklings by their quacks? are they old enough yet or not? I would like to get some ducklings this age from someone but wasnt sure if this method would work at their age. Theyre crested white ducklings that she bought from the "assorted crested" bin at the local feed store. I am hoping they're crested Pekins, i'd like to get a couple hens for my runner drake ETA: she said they are solid yellow with crests. any ideas?