I fed medicated feed to vaccinated chicks - now what?

[ranchokelly]

I just did another post, as I have 6 chicks about 2 weeks old and one isn't doing well, suspected coccidia.
They were vaccinated and I've been feeding medicated feed, and on here it says that will void the vaccination. So now what? Switch to unmedicated? Treat them for coccidia? Only one is showing any (possible) symptoms - she's weak, listless, not growing like the others.
Should I treat just her or all of them?

 

[Kelsie2290]

Sorry about the problems with your chicks. If one is showing symptoms would treat them as the dosage for treating an active infection is a lot higher than what you have in medicated feed as a preventative. And would treat all of them since they would all probably be infected, some just not showing signs at the moment. Thread great post with dosages on it https://www.backyardchickens.com/t/818879/updated-corid-and-amprol-amprolium-dosing

 

[casadezorola]

For future reference: should I NOT feed medicated feed to vaccinated chicks?

 

[Kelsie2290]

X2, you do not want to feed medicated (for control of coccidia) feed to chicks vaccinated for coccidia or you nullify the vaccine (The vaccine is actually coccidia but in low numbers so the chicks just get a very mild infection and hopefully build up their immunity to it gradually before they are exposed to greater numbers outside etc.. so if you are giving the chicks medicated feed it is just killing off the coccidia they were vaccinated with.)
http://www.merckmanuals.com/vet/poultry/coccidiosis/overview_of_coccidiosis_in_poultry.html

 

[ranchokelly]

Thanks for the explanation - that makes sense!
As it turns out, the breeder got back to me and told me they were NOT vaccinated for coccidia, just Marek's.
So I'm now giving them Corid and hoping for the best.