Definitely larger shavings. If you didn't have shavings you could use paper towels, but nothing with "loops" in the fabric that they can get their toes stuck on. Large shavings are the way to go, IMO.
I'm so sorry for your losses!
If they're not acting too cold or too hot, I don't think heat is your issue (personally). We have brooded outdoors even during wintertime and our chicks have done well with it. Sounds like you removed the sticky stuff, so that is good.
I was instantly...