Your asking the wrong questions IMO.

The first question is why would they not show you anything but what appears to be the call working like magic? They are the ones to profit and have to show you they believe it to work.

The second question is has anyone actually heard a live hen squealing like this in the wild?

I've seen hens bred but never heard it. It's one of those bad examples of trying too hard to create the next gadget!

save your money!