Do you see any neurological signs?
Keep the chicks in a hot place give them a good quality food, crushed boiled egg, some canned tuna fish, you can give them some extra vitamins.
Beware of a secondary bacterial infection! Especially in the respiratory system. They can use the damaged that the virus caused as a platform to enter the bird system! Be shore that you have some broad range antibiotics in hand! Just in case if this happens!
I'm not sure. It started with a weak leg and curled toes and happened when I gave them plain water instead of the probiotic/electrolyte water. Quickly became total leg weakness; it cannot stand and lays on it's side. Its legs twitch and spasm. Its head also twitches. Today there is considerable facial swelling.
I had it in a separate crate on top of the brooder because until I found the swelling, I thought it was a vitamin deficiency. That crate was right next to the heat lamp, so it has been extra warm but not on purpose.
I'm having trouble finding info that I can process. Most of it is too thick to wade through.
That's about how old mine were. You have any e capsules?