Thanks... It's aspen. I thought that a lot of people used aspen and it was safe. I got it at a snake show, actually, and I've never seen anything to indicate that it was dangerous. If I'd known at all that this could happen, I would've used something different... I guess I thought if it was a problem, so many people wouldn't use it... and that a creature whose stomach could digest bones wouldn't have a problem with the little bits of substrate that got on the mice.

The weird thing is, the last time I fed them was a week ago and he acted completely fine even last night.

I just don't even know. This is so terrible. He was so beautiful and I loved him so much. Had I gotten even the slightest indication that anything was wrong at all, I would've taken him to the vet immediately.