The bulb idea makes sense. It did just occur to us that this bulb was relatively new and was not bought at a farm store. It was bought at a hardware store. We had no idea that it could be toxic. That makes sense and we feel terrible. Good to know so it won't be repeated. Thank you so much!
You may want to try MHP (heating pad), there's a thread by Blooie (that's LONG) worth looking over. I tried it once and that's the way I raise chicks now. Just don't do what I did, over think the simplicity of it all Again sorry for you loss and raising animals is an everlasting learn curve.