I'm so sorry. chicks are fragile creatures, and might have died no matter what you did.
Next time, try a heating pad set on low. Put the chickie box on a towel over the heating pad. That provides gentle radiant heat without possibility of carbon monoxide. It worked for me!
Next time, try a heating pad set on low. Put the chickie box on a towel over the heating pad. That provides gentle radiant heat without possibility of carbon monoxide. It worked for me!