It’s more likely eggs and they may not have hatched so that’s why you empty the bag before the do.
Strangely hamster food is absolutely fine after freezing. You would think it would get damp defrosting etc but it doesn’t it stays dry as a bone. I think it’s because it’s dried food and the bag is probably airtight.
I take a whole bag out of the freezer, leave it an hour or two and then tip it into a lock and lock box where it stays fresh and dry. Been doing it for years.
Or you can leave the bag in the freezer and just get out what you want each day and let it defrost. I think an open bag is more likely to get moisture in though.