Breeding with layers who eat medicated chick starter?

[vpeterson]

Will the medicated chick starter effect the unborn chicks?

 

[ChickenCanoe]

The medication interferes with the metabolism of thiamine (B1) in coccidia.
I don't know if it blocks absorption in the chickens' intestine but here is a link to effects of vitamin deficiencies.

http://www.merckmanuals.com/vet/pou..._poultry/vitamin_deficiencies_in_poultry.html

I do know that a thiamine deficiency in breeders causes polyneuritis and dead embryos during the last 3 days of incubation.