My Cochin bantam chicks are 2-3 weeks old. They've been doing great. Then I found my oldest chick spinning circles in my brooder. Couldn't upright herself so we put her down. Then 3 days ago I noticed 2 others starring up at the sky. Not moving as much & seem to lose balance. Then they flip over backwards & flop around! I just had 3 do this today!! They are in a big metal tank, heat light but they can get away from it. I did add Corid to their water for a week from cocci but that was 10 days ago. I do put a little ACV in the water & on chick starter from the local MFA mill.
Sounds like wry neck or another vitamin deficiency. I'd recommend starting them on a vitamin supplement such as NutriDrench. Take a good look at your feed's ingredients - it could be lacking in some way. Corid may also have had a hand in this - it can affect chick's thiamine intake if too much is given, what dosage did you use? Are they vaccinated for Marek's? How is your feed stored and is it fresh?
So sorry. Google "crazy chick disease" http://www.thepoultrysite.com/publications/6/diseases-of-poultry/218/vitamin-e-deficiency/ Quote: Source: http://www.merckvetmanual.com/mvm/p..._poultry/vitamin_deficiencies_in_poultry.html
For chicks I did 2 cc in a quart of water. I normally do 10cc per gallon when I treat my big pens with Corid. That doage was given to me from the vets at the University of Missouri My feed is stored inside my house & I just fill up a bucket when I'm low. I have electrolytes I can add to their water. I also have BoSe which is Vit E & selenium that I Give my goats Not sure if I could give a chick a shot .