This last week I've added two new hens with my 7 month old hens. Now there has been some pecking and bickering but the problem is my 3 hens don't want to go int o the coop at night. They free range most of the day while the new girls will chill in the run and around the coop. I have an automatic door that shuts in the evening but I found that they have been hanging under a tree cuddled together. Any advise ?