Where do you have the genotype testing done? How do you trial them for immunity?
Cornell bred the K and C strain Leghorns that had only a 3% or so death rate from Marek's.
The immunization does prevent tumor growth in most cases and it has to be done on the first day of life.
I think you trial them for immunity by by having the ones that catch mareks die. Dead chickens have no chicks
I personally don't think the average backyard flock can keep their chicks unexposed to maraks for long enough for the vaccine to ttake effect. 14 days is a long time to not get exposed to dander by you seeing your other chickens. And if it is outside with a broody? Even less chance.
The hatcheries vaccinate in the egg So they come out immune. And even that is not a sure thing.
The last talk I had with us Davis on the topic just depressed me.
Clearly you have done some research on the topics too so I'm interested in your opinion
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