Mine sing. Likely because they grew up in the brooder listening to opera and Broadway albums! Phantom of the Opera was a huge hit, Sweeney Todd, not so much.
We have the laying an egg song: Buwaaaa---uak! Buwaaaa---uak, bwack, bwaaack!
We have the happy to be alive song: (I cannot begin to write it up, imagine the Charge of the Light Brigade and it'd be close enough)
We even have the "Come feed me, lady": BWACK-ACK-ACK! (usually accompanied by Scarlett tapping on the bedroom window)