I have a deadly respitory illness wiping out my flock. I have cleaned the coop, separated the sick from the healthy, but still, whenever one shows symptoms, it is dead within 24 hours. Starts with droopy wings and head/lethargy. I immediately treat with vet rx, they are treated with antibiotic water as well and I recently started another waterer with electrolytes. Just doesn't make a difference. By the time the symptoms show, they slowly suffocate to death. What is this? Do I need an injectable antibiotic? These birds are polish and are about 4 months old. Please help!!