urbanMike
Chirping
This is a hormonal thing, they tend to calm down quite a lot once they begin laying, vs the more frantic, run-from-everything teenage phase.
I'd say a chicken's friendliness is a combination of inherent breed qualities + their individual personality. Of my initial group of chickens, one was added 7 weeks after the original chicks (all same hatch dates, just bought later on) and was a lot more terrified of people at the start. But now that she's an adult she's plenty friendly enough - no one would be able to pick her out as the one that didn't have human contact at the start of her life.
I worked with them the past few weeks to associate people with food. They're all used to being picked up now. And not having freak-out sessions. I think one the big differences is our first batch we got literally the day after they were hatched at the hatchery and this batch was a few weeks older when we got them and spent more time on display in a box.
They are getting pretty big now.