Hi, Kate, I'm going through it, too, and have been flailing. 100 Freedom Rangers on pasture in this first batch, and I think I've lost about 15 to coccidiosis at this point.
I got mine through the first round of Corid, and only lost three. All seemed healthy after that.
According to everything I've read, you're supposed to give them another run with Corid two weeks later, to kill the parasites that hatched from eggs left inside the chickens. Which I did...
Unfortunately, after completing the second round, I started seeing more sick chickens and lost several.
Edited by mountaingirl196 - 6/2/16 at 5:53am
Based on things I've read here on BYC and elsewhere, I've modified my approach, and this seems to give them a fighting chance. I isolate the sick ones and have them under a heat lamp. Each is getting straight Corid in an eyedropper in the morning (one drop per 100 grams weight, weigh your chickens.) I'm putting a little more than they're supposed to get into the syringe, as I'm not shooting it straight into their beaks in order to avoid sending it down their trachea and giving them Corid pneumonia. It's a bit messy and some of it ends up not in the chicken. Their water is spiked with electrolytes and Bragg's ACV.
If they're too far gone there's not much hope, but if you start treatment at the first scintilla of symptom, it seems to be effective. The ones I have in my infirmary now seem like they're going to make it, as they've started eating again. It still hurts them to pick them up and give them the Corid, I wrap them in a towel to keep them secure during the procedure.
They are extremely weak and vulnerable right now, I had one literally scared to death when I was taking her from pasture with a goal of getting her back to the house and the infirmary. A neighbor's dog ran up to say hi, and she died in my arms. My neighbor felt awful, as did I. That one didn't seem that sick, I was hopeful of being able to pull her through.
I've gone several days without seeing more sick chickens, and am hopeful the survivors have finally developed enough immunity to pull through. Knock wood.