If you only bought a few (or just one) from a large brooder full of keets then they will cry for their hatchmates/broodermates for a quite a while. They are flock oriented even at a young age (they instinctually know there's safety in numbers and they feel they got left behind and are crying for the others hoping to be found). If one mirror doesn't work, try 2. And I have not had to try it myself (since I have a constant flow of newly hatching keets), but I've heard the radio does work too.