Lots of good ideas & suggestions for taming chicks/chickens into "PETS"...
Am new to chickens, but VERY experienced in animal training, handling, etc., etc... And one philosophy holds true REGARDLESS of species:
In order to have an animal really WANT to interact with you the POSITIVE must outweigh the NEGATIVE.
This is *NOT* to imply that anyone here is trying to be "mean" or "scary" to their chickies... Everyone I've seen on BYC seems to want nothing but the best for their feathered friends!!
It IS, however, a matter of perspective... You kinda gotta "think like a chicken"; what ARE they, how do they naturally behave, what is SCARY (large things rushing towards them, things swooping down from above, being alone, etc.) and what is safe & pleasant (FOOD, companionship, slow-moving "smaller" stuff, etc.).
If you can get them to make the initial association that YOU=POSITIVE (by sitting quietly, just spending time around them, treats on hand, etc.), and minmize the YOU=NEGATIVE (from THEIR point of view!!) by being careful not to startle them, looming above them, loud noises, etc... I'm sure they will come around.
Also be careful not to accidentally "punish" them, for example if sitting quietly & one DOES get brave and come over to investigate, get a treat or whatever, reaching out to pet or pick it up may be considered "negative" by the bird if he/she is not ready for it yet. ("I got brave and went over to her, but she SCARED me, so I don't know if I wanna do THAT again...")
After you establish the initial YOU=POSITIVE, they will tolerate and probably come to enjoy, more & more "hands on" interaction.
Something else that was already mentioned, is using a specific sound, words, whistle... whatever, but something easily recognizable by the chickens, that they can learn to associate with POSITIVE, food probably being the easiest choice as a "reward"... Use the sound/whistle EVERY time you feed them or toss in treats, will be a good start/useful tool in training them to come to you!!!
Good luck!!