My rooster started making this noise today. I was in the chicken coop with the hens and he was on yard roam (I allow the roos to roam but not the hens as much, we have huge hawks and I wouldn't mind the loss of the roo as much). He was making that noise and just within 15 or so minutes my barred rock hen laid her first egg. No one sang an egg song but she did sit in my lap and talk to me all about her new egg.