Indications that a cockerel isn't worth keeping around for fertile eggs include biting, wing flapping, flaring hackles at you, not getting out of your way, 'stalking' you as you do chores, or dipping his shoulder towards you. You also don't want to keep a boy that is too rough when breeding the...
Depends on if he turns into a jerk or not. At only 8 weeks old, he is still just a baby. It's not until after 20 weeks or later that a male really starts to show what kind of rooster he has the potential to become.