I have 15 9 week old chicks that are picking on each other. I have them in a chicken pen/coop that is designed for the amount of chickens I have, so they have room in their to move about. I feed them Purina Starter Grower Feed, have 2 feeders in their coop, plenty of water. I fill their feeder and waterer 2 times a day. What on earth is going on with these girls???? My 1st flock didn't pick on each other like this and they lived in the same coop/pen until we got a bigger hen house and run. I'm waiting for these chicks to get bigger to put them in the run/house with the older hens. Any suggestions of what is happening here?