Breeding for Mycoplasma resistance?

[Glorylandfarms]

I am wondering if any of you are breeding for Mycoplasma resistance/ immunity. Long story short, my flock came down with MG from wild birds. This flock is only a year old, so I am convinced that restarting my flock would end up with the same results in another year or two. I figure that I have two choices: cull my flock and give up the hobby, or keep my flock and breed for resistance. I'd say half my chickens got sick on the initial outbreak, a few quickly died, some seemed completely immune. I am now breeding the resistant birds. If they never got sick, are they still carriers? I'm assuming so.

I was just wondering if anyone has tried going down this path, and if so how did it end up? Did your flock eventually become immune? Or was the experiment a failure?

May I ask how it worked out?