I believe this is Coccidiosis. It's very common when they're young and easily chilled. Sugar water with crushed garlic in it seems to help. I combined sugar, water, and as much crushed garlic juice as I found palatable and then used an eyedropper to put it down our chick's throat. It seemed...
One of ours did this at 15 days old, gasping non-stop as if she was screaming, but no sound. I'm brand-new to raising chicks, so please do your own research, but this is what we did, and she seems to have recovered. Hope it works the same for a 4-day old, but I really don't know. Mostly they...