Update:

Thanks for the replies, so now I know the scope of whelping, lol. We are having some luck here, the aggressiveness has diminished greatly. Couple things we think we may have corrected: I don't think we were feeding her enough and maybe she was having problems producing enough milk. We've padded the pen more to make it more comfortable for her. We've bumped the heat up another 2 degrees. You can kinda tell when she is getting a bit crabby and we separate her from the puppies for a little time. So far we've only had some quick nose pushes so maybe we're on the right track. Thanks for all the help, I'll keep you posted.