I don't raise chickens to be petted, probably because it reminds me of this:
But as for teaching them not to be scared of people... I find it helps to raise them in heavily frequented, but not super busy, people areas.
For instance; our back porch works great because we sit out there several times a day, but we're not running around out there either. So, they get used to us watching them, and used to us talking. They don't expect us to invade their space, so we get to see their normal relaxed behavior.
This of course does not help a whit with necessary handling for health or relocation purposes. I just treat that like what it is, an imposition on their bodily autonomy, and get it over with as quickly as possible.
This is not to say that my method or reasoning is the best, just to explain it.
... and then you have those few... ours is Susie Q. She wants to know "what do you do?" and walk around the yard with you. Watch your step! Don't let her see you leave! Shh, be quiet, it's time for scratch, but I don't have my shoes on yet. Is she a pet?