Saving chickens

So recently I've been saving baby chicks around my house and out all that I've saved 4 of them had made it throught but I've had a couple that had passed.

Recently I saved/found a baby chick (who possibly just made 1 week) on my door step and took it in and tried to help raise it. Today however, I had noticed when I came home from work my baby's energy had dropped alot. She is very limp and laying on one side.

I've been nervous for the past few hours because previously when I saved other baby chicks they showed the same symptoms before they have died hours before they have taken their last breath (I've actually had a couple chicks die in my hands as I tried to save them)

I was just curious on how & is it possible to help save them?