1. MG is transmitted at a rate of 1%-10% of eggs, so not all eggs from an infected source will have MG
Sorry but I don't like those odds. If the heat treating kills the infected eggs that is much better odds.
I also see no difference from buying eggs on here as
ebay, many egg sellers are selling on both, and both have feedback. And from the information I received from a national poultry company that almost all free range backyard flocks are infected or exposed. He is who I turn to for information such as this when I can reach him. He gave me the heat treating information. At the very least on
ebay I can be assured most the time I am dealing with an adult. My one and only experience buying eggs on BYC was disappointing to say the least.
The fact is that almost all wild bird population are carriers and no matter how good your bio security is if you have a outdoor free ranging flock they are and will be exposed. As I stated outlook for a clean flock living a happy chicken lifestyle are grim. As posted by another member even indoor closed flocks cannot be contained from the disease.
My breeders for eggs I sell are in chicken tractors so there is no contact with wild birds or limited, but my free range birds have been exposed to crows, cardinals, robins, wrens, bluebirds, mocking birds, starlings and so on. This is a problem with closed indoor commercial flocks that these very small birds are hard to keep out. This is why they vaccinate, and as already posted it is not 100% protection unfortunately.
If heat treating does not destroy all the eggs but only the sick ones it is the best option, IMO.