i would call the hatchery, and ask them,, see what their response is,, because from my untrained eyes,, your doing everything right,, so dont blame yourself,,its got to be something WAY deeper then your care,,,tomorrow ill ask a few people to look at this thread and see what their thoughts are,,,,,and i am so sorry your going through all this,, is not right!
So sorry to hear about your loss. We have also lost some baby's to unknown causes but ours did something similar they became lethargic and teetered over alot they appeared to nap aot to and become distant from the others. some said it could be cocci and some suggested antibiotics so I tried that and the rest seem ok and the sick one appears better. but you need to know what kind of antibiotic to use depending on what they have got. I also added vitamins to there water to help with the extra boost. I found all these things at the local feed store. Good luck with your baby's.
I just lost 4 chicks to the very same thing resently...they acted the same as you described. It really does stink! Mine were some banty D'uccles I'd been wanting and now I only have 2 left!! I'm afraid they will die too.
I tryied giving mine electrolytes...that didn't work.
They would eat normal but then act all sleepy and go down hill from there...
Mine are from Ideal though...hmmm.
I'm sorry bout your babys ='(