Good luck! Gentle pecks by a broody can be a way of disciplining chicks "hey, you, what are you doing wandering away?" My current broody pecked her adopted chicks (gently) quite a lot when I first gave them to her. In her case, I honestly thought she was confused about where all these guys came from. She settled down after a few hours and is now an excellent mother.
But, if she pecks them hard and begins hissing at them or chasing them away, that means she's rejecting them and you will need to brood them yourself.
But, if she pecks them hard and begins hissing at them or chasing them away, that means she's rejecting them and you will need to brood them yourself.