Cochin bantam hen

Pic of problem hen in front

Hi all, I’m reading that Cochin bantam hens are supposed to be a friendly, docile breed. I know my rooster certainly is towards me. However, I got 2 from a friend just yesterday and one of them definitely has an attitude problem. I was told they were very sweet, friendly, and she could easily pick them up, which is true. But this one hen has been pecking the crap out of me, in a not friendly way. I mean she is grabbing my skin and making sure it hurts, leaving a mark if I do calmly reach out to her. I have neither struck her with my hand or kicked with my foot (which I’m not planning to do at all), I simply let her peck me without a reaction because it’s not going to scare me off. I’m not scared or anxious of her, I can only assume she is scared and may feel more dominant towards me by showing her butt in a new environment. Other than holding and treats, what else could I do for her to make her feel safe and that she can trust me?