I have never had a female yet that could whistle. I wish someone on here would say they did but so far I have not seen a post that said they did. Mine whistled at 2 weeks. I am not sure if it was one or both. Hopefully it is only one and I have at least one Hen. Good luck with yours. I hope you have Hens also and not a bunch of drakes.Whistling means drake? My female runners are almost three weeks old now and they chirp and whistle. I swear they sound almost just like crickets! I hope you only have one drake too. I’m still a nervous mess on the gender on mine!