Sorry, my mistake. The intent is to address coccidiosis. I had used Valbazen several months back, but there were still some persistent issues with poopy butts/eggs and so the vet recommended trying Corid (especially because my yard is very wet).Welcome To BYC
Is your intent to deworm your hens? If so, then use a dewormer like Valbazen. Dose is 0.08ml per pound of weight given orally once, then repeat in 10 days.
Corid is a Coccidiostat, it is not an anthelmintic (dewormer) so it will not be effective in treating worms.
But after I put out their medicated water, I remembered that one of the chicken products I'd used in the past had a "Not when molting!" warning. I was relieved to find that it was not the case with Corid.