I've been buying roughly 4-5 months of prey at a time, three different prey items/sizes.
I then weigh and sort them, place 3-5 pieces in zip-locks (squeezing the air out best i can) and label them. The zip-locks are then put in large gallon size freezer zip-locks.
This allows me to only open what I need, the rest remain air tight.
No issues at all so far.