My understanding is that Corid,
mimics thiamine not blocks it.. and the coccidia feed on the fake thiamine ultimately being starved out to slow their growth/reproduction but doesn't actually kill them thus allowing for some resistance to build. Or at least that's what their website says..
https://www.corid.com/CoridProducts.html
IF/when Amprolium is no longer effective against coccidia.. then a sulpha drug can be used. Resistance is a KNOWN fact.
Some chicks just don't make it.. regardless of coccidia load. Questioning the symptoms, day of passing, etc.. and identifying if there really is need for treatment/prevention aside from standard good husbandry.
I think I'd just hatch less chicks, create less crowding. But this much I do know.. the more chicks you hatch the more things you will see and experience. including failure to thrive, genetic weaknesses, possible deformities, etc. Let's not forget things like Marek's and so on.
FWIW.. using
medicated feed is LOW dose and may NOT be enough to prevent coccidiosis in an individual environment, therefore.. drench or treatment dose with Corid (or sulpha drug) may STILL be required and the medicated feed may be leading
some to a false sense of security and won't even consider coccidiosis when it starts to hits.
Introducing chicks to the soil slowly as indicated by another poster has made a huge difference for my juveniles going outside staying well.
I'm not against medicated feed or Corid.. I am against over use of anything.
Dear OP, with high stock density.. you might consider treating your ground, discussing it with your local agriculture department (or veterinarian) to see what's still working or not in your location.
If you're not already using a nipple type water system.. that might be an option.
Best wishes for thriving and healthy chicks!
