A hen, or multiple hens teaching a young cockerel by bullying him is quite common to see.
Many people put their misbehaved young cockerels in a flock with older hens to teach him manners, and it usually works well. Although, sometimes you will find a cockerel who does not get taught anything and stays his hormonal self. Overall, it is the job of the hens to teach him what he is supposed to do and what he is not supposed to do at a young age—which is usually when he begins trying to mount the hens.
Do not worry about your cockerel getting bullied unless he is developing wounds.
Many people put their misbehaved young cockerels in a flock with older hens to teach him manners, and it usually works well. Although, sometimes you will find a cockerel who does not get taught anything and stays his hormonal self. Overall, it is the job of the hens to teach him what he is supposed to do and what he is not supposed to do at a young age—which is usually when he begins trying to mount the hens.
Do not worry about your cockerel getting bullied unless he is developing wounds.