I have finally (FINALLY) been able to notice a difference in the ducks' voices. They are 2-3 months old (not sure exactly, don't keep track). Of the 5 ducks, there is 1 definite female Pekin. The other 2 Pekins and the 2 Khaki Campbells are very quiet and whispery. I'm so disappointed. I wonder what are the chances I could find some Khakis and/or Welsh Harlequins locally that are about the same age.