I heard that once you have MG in the flock, there is no cure and the flock you have will need to be isolated from any new chickens…(which means no more new chickens ) all you can do is just maintain the flock you have now with antibiotics to ease the symptoms when they are sick.. I currently have two recently purchased pullets that have come down with a respiratory infection.. I started treating with VetRx , oregano oil, and rooster booster, not getting better , but not getting worse, so I decided to start on LA-200.. my manager at Tractor Supply said to add 2cc of LA-200 per gallon of water… going to start this in the morning.. going to use for 3 days.. then see if there is an improvement