Audrey:

keep those bins. Your worms may be dead but I am sure there are some or even lots of worm-eggs in them and the baby worms will hatch when the weather gets warmer.
It is a good thing you have insulated the bins now to prevent repeat freezing.

I believe that is what happens outside in the open anyway (on the ground) when the ground freezes. We get baby worms in spring. Good luck.

Otis

Thank-you so much for your response Otis ! I will be more careful next year!

I have the other problem... too hot!

I do what I can but there are times the 'kids' just take a hit. Do what you can, when you can and don't over feed them when you see them come back. Numbers are reduced but they will recover soon. Those eggs are tough and some adults may be holding on in the center just due to heat generated by the natural process and the insulation provided by the bedding.

You got great advice, do what you can to protect them and let the bin populations heal. Good luck!