I definitely agree with this last point. In addition to human & chicken feed storage, I use buckets for general storage and making self-watering planters. They fit well inside each other, so it is easy to keep extras in a single stack.Not to beat a dead horse, but if you take advantage of those "free" 5-gallon buckets at the bucket day sales at the tool stores, you don't have to use them for food. I have a number of 5-gallon buckets that I use to tote around tools, use as garbage pails, toss in bits and pieces of a work project, etc... Mostly, those are 5-gallon buckets I have saved from painting or maybe drywall mud. Just wash them out and use them for a tool bucket. If I don't know what the bucket was used for before, then I would not use it to store food, not even dry feed for the chickens. There are countless uses for those 5-gallon buckets.
At any rate, I hope some people will consider taking advantage of those bucket day sales and save themselves $5.00 per bucket. That's a good deal that I suspect lots of people don't know about. Those 5-gallon buckets can be useful for lots of things, and I have found it very handy to have empty buckets and lids around in my garage.
FYI- Some people use the larger kitty-litter buckets in a similar way. I have no knowledge of their food-safety factor, but wouldn't hesitate to clean them out and use them for non-food storage and their squarish shape is actually more space-efficient.