I have the nastiest little batch of chicks. It doesn't matter what I reach down for at their level, one of them will come over out of no where and latch onto my hand or arm. They have even tried biting my leg!! It makes it easy to decide who is going to be dinner first.
Be careful making that decision. They usually grow out of it. They do it because they are scared. Are they just being floor aggressive? Do they act nasty when you are holding them? If that is the case it should go away.