Why do hens make so much noise when they lay?

This is probably a daft question but can anyone tell me why hens announce to the world that they are laying an egg?  I didn't realise that they did this and when they first started laying it made me wonder what on earth was happening and I rushed down to see if a fox or something had got into the run!   I have since assumed it is a bit like childbirth - painful!  If they were in the wild it would let predators know where they were and would put their lives at risk.  Any thoughts?

It's a very interesting question. I have never heard wild birds exhibit this behaviour...at least not around here. Perhaps other species do it in other parts of the world.

I read that it is a contact call. In the wild the rest of the jungle fowl would have moved away feeding while the egg was being laid. The hen gives a shout hoping the rest of the harem will answer so she can track them down and join them when they reply.