After raising three previous batches of chicks with poor results as far as producing tame chickens, I decided on a new approach this summer.
I put my brooder box on a table and cut access doors into the side. It was a smashing success! Not only did it calm the baby chicks to see a whole person attached to the Big Hand, but it really saved my back not having to bend over.
I pulled a chair up and sat down when I needed to visit with my babies and clean up the brooder. It was a lot like having a doll house! The babies were tame right from the start, never showing any fear when I reached in from the side. After a few weeks, I'd have two or three of them hopping onto my head and shoulders every time I opened the door.
When I brought them treats, I'd call, "Babies!" and they would all make a mad dash to the door, lining up like little soldiers to see what I had for them. Now that they're all five months old, and three and a half months old, calling "babies!" gets an immediate, conditioned response, making it a cinch to pick up any one I need. They've all grown up to be exceptionally tame, unlike my previous batch who remain impossible to catch.
I attribute this success in taming them solely to the brooder access being from the side and not from the top.