Whatever's at hand. I've thrown buckets before, in general I just lunge at the bird and shove him out of my space until he runs off. It does not need to be excessive, and as noted in that post I wrote, it SHOULD be short and fairly light. Make a point, but don't harass the poor thing.
I have never experienced the pullets picking up on it, so I can't help you there... the aggressive lunges aren't directed at them and they figure that out. They're smart. Use your body language. Actually, many of my hens/pullets are entirely too friendly.