I've had 5 of my flock die of the same symptoms. It happens suddenly, they seem fine the day before. The symptoms are they act sleepy, won't eat and just stand with their feathers fluffed. Then they die after a few hours. I now have 2 that are just starting to have the symptoms.The ages they are range from 6mths- 2 years. What do they have and is it treatable? Please help!