So my mom was talking to a woman who wanted to buy hay from us for her chickens. The lady was a little bit displeased with the person she bought her chicks from by stating that the person had "no clue" about the sex of the chicks. She then went on to say that roosters will have a staccato chirp, and you just need to listen to each chick's voice. She still ended up with roosters anyway. Is their any credence to this claim?