Interesting reading. Another explanation I heard was hens typically lay approximately a dozen eggs before going broody ( obviously this can vary widely). If they lay an egg a day and raise a ruckus for 12 days straight,and no predators have found the nest , then it is likely a safe place to broody. Then they go full stealth with very little movement or sound while incubating the eggs.
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BY Bob
This is very interesting. I have never heard this theory before. Thanks for sharing.