Excuse the long post, but I am really unsure how to proceed and could really use some advice. Three of my five hens have suddenly turned on my black Australorp hen Kellyanne and are not letting her out of the roosting box and viciously tormenting her when she tries! I have five hens (two Rhode Island Reds, a Barred Rock and two Australorp) and they were fine until a few days ago. Kellyanne has always been on the bottom. Relevant back story: Kellyanne went broody some time ago and sat proudly and purposefully on some fake eggs for a little over three straight weeks. I swapped out the fake eggs for four day-old chicks on her third week and she has been a very attentive mother to her chicks who seem to be thriving. The chicks are now three + weeks old. Kelly had been raising them in a large dog crate inside the run. I kept the crate open and Kellyanne and the chicks mingled with the rest of the hens peaceably during the day in the run, and in the yard each afternoon/evening. My enclosed run is 70 square feet and roosting box 26 square feet which I am pretty sure is big enough. A few days ago something changed and Kellyanne abandoned the crate and moved herself and her chicks to the roosting box where I then put food and water. Kellyanne is unable to leave the roosting box without the top three hens pouncing on her viciously. She lowers herself respectfully and they all just stand on her and peck her. It does not stop until Kellyanne runs back to the roosting box. The hens do not interact with the chicks and only intersect them when they go into the roosting box during the day to lay. I have read that I should perhaps take out the top hen, but in this case it is the top three hens that seem to be the problem. I have been hoping that things would just settle down, but I am worried that things will escalate if I don't intervene and that I might be putting the chicks in jeopardy with my inaction. And I feel terrible for Kellyanne. The hens are a year old, eat layer pellets supplemented by lots of veggie matter and get out of the run every afternoon/evening for a few hours. I live in San Diego and the weather has been in the 70s and lovely. Any advice would be greatly appreciated. Thanks!