For some reason this last week my hens (5) have been so noisy! One morning at 5:30 they were out having a clucking chorus - so after that I started shutting them in their coop and letting them out when I wake up, which is around 7:30....and right now one of them has been going off and on for an hour!
Maybe they're forecasting the rain.
My girls do the same thing, on and off through out the day... and I always presumed it was the singing of the Cackleberry Song....the exuberance they express when an egg has been laid. This is prime egg-laying time for most of them, too.
Hens are noisy! Some more so than others. People worry about roosters, but my hens make more noise than my roos.
Usually they squawk when they lay an egg, but also if there is a perceived threat. If they see hawk (or a pigeon that looks like a hawk to them), they squawk up a storm.