I just noticed a hen with one eye closed, just standing around. At first I thought she was sleeping, but when I approached she moved and I noticed one eye closed. From time to time she would open it, then close it back. I picked her up and she was shivering a little and her crop feels really large. I picked up another hen and her crop seems much smaller and lower on her body. The other one won't extend her neck when I sqeeze gently on her crop. The eye looks okay - no swelling, puss, etc, just closed. Otherwise she looks fine. She's a 9 week old Dominique. Any idea's?