Hello and welcome to BYC!
Glad you joined.
I agree with @janiedoe that the unbalanced chick should immediately be started on a quality poultry nutri-booster along with vitamin E and selenium. As mentioned, egg yolk is a good source of selenium.

I agree with @janiedoe that the unbalanced chick should immediately be started on a quality poultry nutri-booster along with vitamin E and selenium. As mentioned, egg yolk is a good source of selenium.