We have separated our three 11 wk old pullets for 2 weeks from the older ones age 8 months with a wire fence so they could see each other. One older bird flew over and was picking on all three. Can the older birds injure the younger ones while being introduced? Also, our poultry man said when we're ready to incorporate all, put the younger ones in the coop after dark. When they all wake up they will be accepted as the group. What has anyone done that works? Thank you.