Please don't euthanize by freezing, it's totally inhumane and there are way better methods of going about euthanizing a feeder.
If you don't mind feeding live I would just feed off the mice if the smell is unbearable and see if your snake will take f/t. If you only have one snake that may be a better route to go then breeding your own feeders.
For rats, I've been enjoying breeding them and raising them up and I think my bf has too. They're really easy to care for, and they don't smell bad at all (we have four females right now with three having babies currently) and they smell better than my indoor rabbits.