I am so sorry you are having these problems. I don't know where you got them, but they should have gotten to you a day sooner.
I got one batch of chicks from Missouri (I am in West Virginia) and they came in one day. The second batch came from Texas and they were here in two days.
Last year I had a batch come in three days and they never did do well.
I realize this does not help with this bunch of chickies, but perhaps next time you can find a hatchery that can get them to you faster. (I can let you know which ones I have had good luck with, if you like.)
With these guys--have you tried hard boiled egg yolks sprinkled on their feed? Sometimes that helps with chicks that are not doing well. And adding sugar or electrolyes to their water, perhaps.
Good luck. I hope it starts looking up. It should be more fun for you, and probably it isn't anything you are doing, but hatchery problems.
Catherine