We brought 5 bantam hens 8 months ago which were around 6 months old. They live in a good sized coop, live on pellets, mash and fresh veg and their water is changed daily and their coop is cleaned weekly. 2 weeks ago one of our regularly broody hens had spent a few days in the nesting box (we dragged her out for food and water twice a day) I then realised she didn't look right, her eyes were glazed over, lifeless and refused to eat so we kept her overnight inside. She also had watery poop. When I came back from work the next day she was dead. We did a deep clean in the coop, chucked out the food, change the water bedding everything. A couple of days ago I noticed one of our serama hens looking funny, sitting in the corner, eyes shut, all puffed up and tail droopy so we brought her in and noticed she also had watery poop and tonight I came home and she was dead. They both died in the space of two weeks so I am so frightened they may have something that may spread to the rest off them. After the first one died we brought three new hens that are 6 months old, I am so worried they will get it, they are so young and I feel so responsible. If anyone could give me any idea as to what is wrong with my girls I would be extremely grateful.