Does medicated started nullify vaccines given?

[Knock Kneed Hen]

I was told that they do by the owner of our local feed store. It would explain why my unvaccinated pullets (carriers of Coryza) didn't contract the disease but the vaccinated pullets they were put with them did. Do they even sell unmedicated starter?

 

[jerseygirl1]

Hmmm, I think, and I'm sure someone else will chime in, the vaccination is for Marek's, not Corzya. I don't know if there is a vaccination for that. As for unmedicated starter, yes, they do sell it,not sure of the brand, but the medicated contains Amprolium, which either builds up their resistance or prevents cocci.

 

[speckledhen]

Medication in feed is only for coccidiosis, not Mareks or Coryza. It will not nullify any vaccine for those. The feedstore person was wrong.