C.C.
I feel for you. I had a big time biter. I think for my son there were a few factors. It started at MDO and the room was too small for the 6 kids. At the daycares, he was bored, tired and also overwhelmed and we were asked to leave because he was breaking the skin and parents were upset. We finally got him at an in-home daycare with the same amount of kids as MDO, but it works. He is able to sleep when he needs to and is not rushed from one activity to another. Plus he is with kids of different ages. I think he is just more comfortable where he is now. I hope that you are able to get it fixed, because it can be 4-6 months for some kids to grow out of it.
Thanks,
C.