Be sure to conduct 'thorough' inspections on each. Estimate number of bees, try to find queen, any larva, signs of disease, too much or too little ventilation, too few stores.
Not to start an argument but personally, I'm not convinced that providing artificial heat is that helpful especially in Northern regions, as I feel it makes bees too active when they should be in cluster instead, consuming too much honey, possibly giving them a false sense of security :idunno: I'm just not convinced….
We can learn a lot just by methodically examining dead outs.