Here's my experience with taming chicks. I corrupt them as early as possible with food. I think it was the second or third day I had them I introduced them to meal worms. They fell in love with me - love at first meal worm. (Their grow-out pen is sand, lot-sa grit)
I also use a verbal cue whenever I have treats for them. "Bay-bees!" I call, and immediately they line up at attention in a neat parade drill at the gate to their pen.
I enter and sit down on the ground and they all hop onto my lap and try to pry open my fingers. (Because they think meal worms could be in there. They are usually right.) Sometimes I don't have any treats at all, and they sometimes remain on me, climbing on my legs, feet, arms, shoulders, and one may fall asleep against my neck.
Sometimes they hop back down and go about their important chick bidness. But they usually are back pretty soon, climbing on my arms, which are fun because they sometimes go up and down, high up like an elevator. They like to launch from there, trying out their wings. But sometimes all four snuggle in close, begin to trill, and then nod off.
As tame and affectionate as they are, they do not like it when I close my hand around them and pick them up. Sometimes it's necessary like when I have to pry them off my arms and legs so I can get back to my human chores, like feeding the darlings and cleaning up after them.
To sum up, my chicks are about as tame as chicks can possibly be. But they still screech in complaint if I try to pick them up or off of me. I'm not sure I understand why. I'm down at their level, not reaching down for them from above them. Maybe it's because they're only eighteen days old. Maybe it's because it's just not THEIR idea.