Help and fast!

[Aflanders]

If you are seeing blood, then yes. Treat all the newbies with the Corid.

Dose for Liquid Corid is 2 teaspoons per gallon of water or Powdered Corid is 1 1/2 teaspoon per gallon of water. Give for 5-7 days as the only source of drinking water.
Don't add anything else to the water except for Corid.

If you are seeing lice/mites, then treat with permethrin as suggested in Post#4

You mention some were vaccinated - what for? Marek's?

Yes Mareks

 

[Wyorp Rock]

Yes Mareks

Then that has nothing to do with Coccidiosis or treatment with Corid.