Is this normal behavior?

[Joken]

We have a 12 week old Orpington flock of 13 and so far only two are crowing. One of the Cockerels is very aggressive to the Pullets, biting them on the neck and just generally being a jackass. He had a Pullet by the neck this morning and it took my boot to get him to let go. I don't know if this will pass or get worse? I understand dominate behavior but this seems a bit extreme. The other Cockerel although larger is not acting this way and seems to have accepted the number two position. We also have a small Pullet that all the chickens pick on and we have separated her for now. I don't know whether to get rid of the bad actor or let it play out a bit longer. Thanks, Ken

 

[LaFemmeKatia]

I would rehome the nasty one. But that’s just me.

 

[Shadrach]

We have a 12 week old Orpington flock of 13 and so far only two are crowing. One of the Cockerels is very aggressive to the Pullets, biting them on the neck and just generally being a jackass. He had a Pullet by the neck this morning and it took my boot to get him to let go. I don't know if this will pass or get worse? I understand dominate behavior but this seems a bit extreme. The other Cockerel although larger is not acting this way and seems to have accepted the number two position. We also have a small Pullet that all the chickens pick on and we have separated her for now. I don't know whether to get rid of the bad actor or let it play out a bit longer. Thanks, Ken

Firstly, your cockerel is not being a jackass. What he is doing is practicing his mating neck grab from your description of his behaviour. Kicking him isn't going to help. What might help is taking the time to learn a bit about the creatures in your care.
There are some good articles here in the learning center that may help you understand the behaviour you are seeing.