Yesterday I found our fence had been knocked down and that day we lost 2 chickens and 3 more overnight. They were very weak, lethargic, and thick mucus was coming from their mouths. 2 of them were shivering as well. Today 3 more are dying and same symptoms less the thick mucus. 1 of them also popes very water and it smelled horrific and looked almost like it has casings of something in it. Anyone have any idea what is wrong. This is a third of my flock in just over 24 hours.