I need some help. 2 weeks ago I added 7 new chickens to my established flock of 8 chickens. The old ones chased them around and pecked at them throughout the day and since then the new chickens will not come out of the coop into the yard. They stay on the perch and refuse to go outside by the older chickens. Does any one have any advice how to get them to leave the coop and interact with the others?