I have what appears to be a serious bacterial infection that responds to sulfadimethoxine, which treats it but does not cure it, the infection returning within two weeks. Signs are dejectedness, fatigue, weight loss, and diarrhea. Nesting behavior continues but no egg is laid until night, where the hen lays it with her droppings while roosting. Occasionally there will be a soft shell but often times there is no shell, just yolk and white. I've had one death so far. Disease has been active for about 2 months, but I haven't been able to find an answer on what it is. It is only affecting my large fowl flock, and my bantam flock, which lives right next to them, shows no signs. I need an answer ASAP. I don't know what to do now. Thanks.