What dosage of Corid did you use?
I've recently learned to use 1.5 teaspoon/gal for initial treatment instead of 1/2 tsp/gal.
Antibiotics will not treat cocci.
Over-treating can be more harmful than helpful.......throwing too many meds/treatments at once can just throw everything way out of...
I'd be careful over/constantly using any poultry dust or treatment, so you don't create resistance.
Treat when an infestation is present, and use more benign preventatives like wood ash to bathe in when the infestation has been knocked down.
Sevin all over??
Please don't.
Sevin dust (carbaryl) is illegal to use in any poultry as of 2010.
Not due to chicken safety issues, but due to human safety concerns when consuming eggs or meat.
Lifetime withdrawal according to www.FARAD.org