We had 9 hens, all around 2.5 years old. We've had three die within a month of each other. The first one was visibly ill/off when I first noticed. She was hunched over, ruffled feathers, floppy comb, sour crop, greenish/white poop covered bottom feathers, and VERY swollen abdomen. After looking here, I came to the peritonitis conclusion. She died within 4 days of me noticing her being ill. 5-6 days later, her best buddy chicken started showing the exact, same symptoms. After further research, I decided to drain her belly and vomit her (I know it's risky, but...)Tons came up. She also died within 6 days of first noticing symptoms. 7 days after her death another one... exact same cycle. Died within several days. Now, we have 4th one that is acting totally fine, but I noticed a poopy bottom and her belly is full....All that have died are the same, Golden Sex-Links from Atwoods. We also have two EE and one Salmon Faverolle. I did speak with a chicken vet over the phone as a courtesy provided by our local county extension service. He was thinking peritonitis, ascites, or heart failure. But I don't understand how they're dying so close together. I haven't noticed any signs or worms in their poop and gave them wormer just incase. I'm just at a complete loss. These hens are like pets and I've scoured the internet for answers. I have yet been able to locate a local poultry vet here...any idea or suggestions would be greatly welcomed.