Because I don't know about safe calcium levels for songbirds, I wouldn't add much, if any, to bird feeders. Maybe some? As you've mentioned, spreading it anywhere near housing is a terrible idea!
Mary
Mary
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Definitely don't dump the food on your property. If you're not going to feed it or give it away, throw it away. The rats and mice, once they find you - will never ever go away. It's not worth it. You'll then be faced with do I set traps, do I risk poisoning etc...
I naively dumped 200lbs of bad feed (arrived molded from the feed store, they replaced it but did not want the molded food returned, said "dump it") ... and what that started - just don't do it. When we moved the chickens to the new house, it took a while for the rats to relocate. It was disgusting, distressing, and I will never, ever make that mistake again.