3 week old Cornish cross is having health problems

[ChickenNugget89]

I have a 3 week old Cornish cross who has started having what looks like seizures. He'll flop on his side and stiffen up with his legs and wings stretched out, and his eyes will be rapidly blinking and twitching. About a minute later he will get up and be fine, just a little tired.
What is wrong? And what can I do to help him?

 

[1muttsfan]

Low blood sugar (hypoglycemia) can cause seizures, especially in the young - is he eating well? The same size as the other chicks? If he has a primary brain disorder he will likely get worse as time goes by.

 

[ChickenNugget89]

He is a Cornish cross and is over twice the size as my non meat breed chicks. Eating and drinking fine.

 

[1muttsfan]

Hope he outgrows it