Aggressive young silkie

[Popcorn]

I have a two month old silkie of an undetermined gender that is being evil. It was shy and sweet for the first month then became aggressive to the point where it is referred to as the bitting chicken. It lives with two cockerels and two pullets the same age and is not aggressive to them but we are integrating the young ones with my current flock and the silkie challenged three hens over two years old and chased a year old one away from food. I thought silkies were supposed to be nice but this is my first and I must say I am not liking it very much. Why is my silkie being evil?