Let me tell ya, they would really go nuts in the middle of the night and much louder and distressing than a dog barking. Just imagine a four-chicken cacophony of BAWK-BAWK-BAWK-Buh-CAAAHK!!!! Over and over and over.
It's very fast and very hysterical sounding...not a nice clucking sound. Echoing through the neighborhood at 2-3am! It was appalling.
Now, if I don't go out there and let them out in the morning, they'd do it even now. But they thought it was morning in the middle of the night before!
Whew, I'm glad that worked...I was seeing the beginning of the end of keeping our girls which would have been disappointing.