I started breeding this year and I've been using a 20oz canister I ordered off Amazon with a regulator. Tippmann I think the brand is. I can get it filled at D!ck's Sporting Goods (not inappropriate, just store name.) for about $6, but they will not fill anything bigger than 20oz.
I don't have a lot of production yet, so I haven't run through the whole thing. I'm just breeding for my own collection, so I think this size will last me a while. I am mostly planning to do bulk batches for F/T rather than weekly to feed the snakes, so it will be used less often that way.
I think bigger canisters like 5lb or larger from brewing or restaurant supply uses are better if you plan to breed and cull a lot of rodents. And if you can find a place that refills them that isn't excessively expensive like the few I found near me.
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