Brewer's: Rule the Roost
(To). The cock rules which of the hens is to have the honour of roosting nearest him. (See under Roast.)
“Geate you nowe up into your pulpittes like bragginge cocks on the rowst, flappe your winges and crowe out aloude.” —Jewell.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894