
You may want to up your dosage on the Corid, normally it's best to give the "severe outbreak dosage". Corid is mild and won't hurt her even if Coccidiosis is not the problem.
Corid dosage for Cocci is 1 1/2 teaspoons Corid powder per gallon or 2 teaspoons of 9.6% Corid liquid per gallon. Make this the only water available.
I fear that she may have something else going on, infection or some other illness since you lost LuLu too. If you do send her for any testing, please let me know.
It's hard to see them suffering, I'm very sorry, I know how this feels I put one of my lovely hens down earlier this week - never easy, but something that we all must face if we keep chickens.