Yes, that is what happens over time. The ones that live and reproduce will pass on some resistance.
Thanks for clarifying that, Ron. I'm in complete agreement with you. I know the bantams that I started using my neighbor's eggs, non vaccinated Amish birds, have seen losses but not nearly as high as with my 'resistant' bred birds.
It makes me wonder if there is a degree of resistance in thise older flocks. They came from a farm within the 5 mile danger zone that you read so much about.
If so it just helps strengthen the idea of breeding for resistance in a Marek's flock.
