I'm so sorry about your chicks. We're on our second batch this year because all six of ours died by 3 wks. This batch is 5.5 weeks and they're starting to do the same thing as your describing, we've lost 3 in 3 days and I have two more sick ones. I feed them hand mixed organic feed, with kefir, eggs, molasses, and nutritional yeast, and now am giving them vitamins and electrolytes from the feed store. I clean them several times a day, check thier butts for signs of pasty keep their food and water clean. I've even been getting up at night every 3 hours to make sure they are eating and drinking(hand feeding the ones that can't get up). They are very well cared for, so I don't understand why I keep losing them, it's so frustrating, I wish I could help them.
I hope you have better luck with your next batch of chicks.
I hope you have better luck with your next batch of chicks.