Okay, first, are both dogs neutered? In any case, yes, likely it is the move that has triggered this behavior, their world is turned upside down, and now they are trying to establish who top dog is in this new place.

The good news is, it's not up to them - the top dog is you! I would spend time retraining Biscuit, as he seems to have the most issues. Have you done any basic obedience classes with him? Maybe time to do another. Making him more confident and less fearful will help, but more than that, him knowing you are in charge, and reinforcing your bond with him, will help him be more secure, and less likely to lash out at Prairie.