I'm wondering if any of you higher volume breeders could tell me how long Mazuri 6F Rodent Breeder Lab Blocks are expected to last past their expiration date. I picked up a 50 lb bag pretty cheaply and realized after the fact that it was cheap because it had just expired. I've got it all sealed in ziplock bags and the rats seem to eat it just fine but i'm worried that it won't stay viable until I use it up. It's about 3 months past the marked date now and I've still got about 25-30 lbs left.