this is an accurate comment couldn't write it better myselfWith a 4 year old child and the chickens all in the same place, he needs to go immediately. He will attack the child at head level, possibly knocking him down, his feet and beak can leave vicious scratches.
The rooster has given you his warning that he is becoming aggressive. Most inexperienced people vastly underestimate the violence of an attack. They often times try to make excuses for the aggressive behavior. He may back off from you for a while, but he will be watching your child to get a lick in, and more than likely he will attack you again.
Most 4 year olds do run around, that is normal, natural, and healthy behavior, the very behavior that triggered his attack.
If you have kids visit your house, you could be liable for an attack.
I just cannot emphasize enough, that the rooster needs to be contained immediately and culled in whatever way you can do it.
Mrs K