Glad you found it.
Corid is mild and won't hurt her at that weight I would give 2-3 drops, that should be fine.
Then see that's she's drinking the mixed water. Sometimes when they are not well they don't drink very good and become dehydrated, you may need to syringe the mixed water into her...
Make the mixed Corid water for them all to drink. See that she's drinking the water too.
In addition to her drinking the mixed Corid water, give her undiluted liquid Corid at a rate of 0.10ml per pound of weight once a day for 3 days. The undiluted is the "drench". This will give her a jump...
I would treat for Coccidiosis.
You can find Corid in the cattle section of TSC
Liquid Corid dose is 1 1/2tsp per gallon of water and Powdered Corid is 2tsp per gallon of water. Give as the only source of drinking water for 5-7 days. Make sure she's drinking the water.
Let us know which...
Show some photos of where you are housing them, the chicks, feeders, etc.
It's possible the CX are hogging the feed. What are your plans for the CX? If free fed they are going to gain weight quickly. I'm not a nutritionist, but I do know you may be able to extend their life for a while by...