Is it possible they got too cold without the lamp? They need over 90 degrees when less than a week old — with places to escape heat at 10-15 degrees cooler, of course. More here.
If you had appropriate temperature, no Teflon, and untreated wood shavings… the issue may have been some sort of...
I’m so sorry. Use an old bath towel for now and pick up some puppy pads next time you’re at the store.
I’ve never heard of young chicks dying from eating pine chips. Is the wood treated with chemicals? You sure the brooder is the right temperature — warm enough with cool areas to retreat to...