IF The feed you are "recommending" sold in MO is MFA Chick Grower Crumble A, then it contains a SMALL amount of Amprolium.
Couldn't be that though, because the feed you use has "antibacterial stuff" and "antibiotics" So...no...wouldn't be the same thing at all!
Corid is NOT and antibiotic...
Make food available to her.
You mention giving 1/4 teaspoon this morning? This was undiluted Corid yes?
Give her only .10ml per pound of weight once a day - this is the DRENCH.
She needs to be drinking as much of the mixed Corid water throughout the day as possible (IN ADDITION TO THE...
How cold is it?
You mention she got her "second dose"? Are you drenching her IN Addition to her drinking the mixed Corid water or are you just giving her a daily dose?
She needs to be drinking the Mixed Corid Water too.
Washing hands after handling birds is good practice.
Your adult chickens have resistance to whatever strain(s) of Coccidia that are found in their environment.
The chicks might have a different strain or the adults - don't know.
If you are eventually going to integrate both groups then...
You moved them?
Why not just leave them all where they were and treat the whole brood?
You want them to have exposure, they don't need to be in a sanitary brooder - you want exposure so they build resistance to what's in their environment.
Yes. Provide grit. I've never had chicks overeat grit, that's an interesting thought.
Yes. They can have Coccidiosis even if they have never been outside. Coccidia are found in poop and soil. It's very common for brooder raised chicks to have an overload. So I would treat for Coccidiosis...
What does her poop look like?
Have you treated for Coccidiosis? Got any Corid?
I've never had chicks poop blood due to eating shavings. Do you provide grit?