I have a Dominique. He's about a year old, one time he got a little feisty and pecked my 8 year old sister. That was about two months ago and there haven't been any incidents since. I was considering culling him but decided to keep him for now since he hadn't shown other aggression.
With a 3 year old it's risky. She's very small and easy to injure, definitely keep her supervised if you do have her around him. It's also hard to teach her how to behave confident around the chickens. Due to her size he may interpret her as a threat to his flock, or as a subordinate. I'm not sure what I would do with a 3 year old, so I'll leave it at that.
I definitely recommend giving
this article a read though! It's how I raised my roosters and will continue to raise them, and so far they're turning out pretty good.
