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I read, from your words, that you didn't want to peck an aggressive chick because want your chicks to "trust" you, but it really sounds like you think it will think you are mean for pecking it.
It is the Chicken Way to establish a pecking order. That's what they know; it's wired into them. If you don't establish that you're the boss as early as necessary, it will be harder to enforce it. Mama hens peck their chicks. Other hens peck chicks; they are letting the chick(s) know who has more status. You need to do that too. You can cuddle and snuggle with chicks that accept it, but if you don't let an upstart know it is stepping out of bounds, it will not know you're the Boss.
I put my forefinger and middle finger together and thunk the aggressor on the back of the neck, or the top of the head, or on its back. Gently. Just once, unless it tries to peck me again. Then it gets a little bit harder "peck." This is something they understand.
Conversely, picking a chick or chicken up by the legs and holding it upside down can harm them, if done for too long a time. I have never done that to a chicken. Or chick. I HAVE picked up an uppity rooster and carried him around like a football under my arm for 15 minutes or so, and that serves to let him know I'm his boss.
Something to think about, anyway.