This is my second year raising chickens. My first year was bumpy but educational and fairly productive. My flock got hit pretty hard last winter with something pretty nasty that sounds like MG (swollen faces, discharge in eyes, coughing, wheezing, etc..). I took one poor hen to my local AG department for a necropsy and they basically told me "it was sick" even though I specifically asked for a test for MG (they said that they would have had to buy 100 test strips to be able to test my one hen). I lost several hens, but they all did finally recover. Fast forward to this summer. I added a fair amount of new chicks to my flock. Around June I noticed a drop of egg production from 12+/- eggs per day to 2-3 eggs a day, 2 of which where coming from the 2 leghorns I have which layed like clockwork all along. I did notice a couple of hens with a slight cough / sneeze, so I medicated. I started out with sulmet for a few days and saw no change, I then switched to tylan for a few days. The symptoms seemed to all go away. I am just now starting to get a few more eggs per day but all of the pullets I have raised from chicks this summer are coming to laying age. I spoke with someone at the ag department here that was supposed to be an authority, the fellow that sent us to have the necropsy performed. He said it sounded like we had foul cholera. He also recommended that we cull our entire flock once a year and start all over, and if we did not we would just perpetuate whatever illnesses where contracted over the year. I REALLY do not want to have to cull my entire flock every year. I have done a good deal of research and it seems like the general consensus is that once your flock has MG that until you do a full cull and start over they will all have it, and it will be a reoccurring theme.