three days and they smelled? I have 4 adult rats and they only start to smell a good week after I change their cages. What are you using as a substrate? What are you feeding them and most of all, how small is the cage they are in? A really small cage will need to be changed much more regularly than more roomier cages. I keep my rats in large roughneck rubbermaid containers (these are roughly 42"x21"x16"
They only start to smell fast when I have several weaned litters in with the adults. This is pretty much when the babies do their business without the mother cleaning up after them.
As for how many rats can fit in a freezer, it depends on how well packaged they are. If packaged flat, you could stack a fair bit in a small freezer, but I don't see getting more than 25 in a mini fridge freezer...(I don't think there is room for more than say, 4 packs of bacon in those tiny freezers). If you need more than that, I suggest getting a small cube freezer. Probably cost around the same amount as a bar fridge/mini fridge and you will have much more space.
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PHLdyPayne