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The Strict Chicken Politics of Cock-a-Doodle-Doo

ByAllison EckNOVA NextNOVA Next

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Roosters’ pecking order literally starts before the crack of dawn.

When chickens are housed together in small groups, the chief always initiates morning crowing, according to a

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new study published last Thursday in Scientific Reports. But if the top-ranking rooster is removed from the pack, other elites step in: the second-ranking rooster crows if the first is gone, the third-ranking if the second and first are gone, and so on. The result is an observable hierarchy that subverts other environmental cues—like the rising sun—that drive most other birds.

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Pre-dawn crows are subtly timed by the highest-ranking rooster.

To prove that subordinate roosters are capable of crowing on schedule—that it’s just socially taboo for them to do so—the researchers had to first determine that each rooster operates according to its own circadian clock. To do so, they plotted the variation in subordinate roosters’ body temperature over time in the absence of the ruling rooster and found that those temperature fluctuations did, indeed, differ. In addition, any anticipatory predawn cock-a-doodle-dos during this particular experiment did not correlate with the timing of external sound stimuli, demonstrating that these roosters only obey their true master.

The study’s authors wrote in their abstract:

These results indicate that in a group situation, the top-ranking rooster has priority to announce the break of dawn, and that subordinate roosters are patient enough to wait for the top-ranking rooster’s first crow every morning and thus compromise their circadian clock for social reasons.

This behavior distinguishes roosters from songbirds, whose circadian clocks can adjust to external sound stimuli. This might indicate that roosters have more sophisticated social structures than other birds.