For the most part, chickens don't seem to be "petlike" pets that seek out human attention. We've gotten our little flock so that they won't flat-out run away from us (most of the time). They did become more docile when they recently started laying although I don't know if that was from being handled more, or from their hormone levels leveling out.
If you want your flock to be more affectionate, don't treat affection like a punishment (holding them firmly and not letting them go, which will stress them out) and instead treat it like a reward. Start by tossing a little scratch near where you are sitting, adding in some stroking and quiet talk to them, letting them come and go, and eventually they will come eat out of your hand and let you pet them. Some might even seek you out, knowing you are the giver of treats. It's classic operant conditioning.