I just came across an old post that mentions some similar symptoms. Based on this I've deleted my original "this worked for me" story. Good luck.. And please let us know how things go. https://www.backyardchickens.com/threads/help-chicks-shaking-head-and-then-passing-away.684509/post-9260649
Not sure if this will help you but when I had an ill baby chick that wouldn't move, eat or poop (and did not have any sign of pasty butt) I wrapped her in a hand towel and used part of a qtip to feed her water saturated with savachick electrolytes (really, really concentrated) and sugar. I fed...