I agree it has to be on their terms.
My cochin is the friendliest, and I can hold her anytime.
The EE rooster will eat out of my hand, has sat on my lap occasionally, but only when I have treats. he takes them as gently as a puppy, and has never pecked hard like the others. He would prefer I not touch him, and we have an understanding...
The BO are friendly, pettable, and will also sit with me for a time, even without food present.
The Dominiques only like me for my food, but twice have flown up on my shoulder and sat.
The EE pullets are somewhat skittish, but 2 of them will sit with me, and Muffy( has the biggest cheeks, and gotee)actually enjoys being held and will settle down for quite some time, until someone decides to make her move. I find it fascinating, that I'm willing to spend my little free time, sitting with the chickens, trying to figure them all out, and really loving it!