Wiktionary
vb. (past participle of fly the coop English)
Usage examples of "flown the coop".
Before all this could happen, however, Joe showed up at Pacheco's to drop a salt block into the field, and when he discovered his cow had flown the coop he started screaming at Seferino, who just glowered lop-sidedly at him during the five-minute tirade.
Well, the chicken hasn't so much come home to roost as it's flown the coop, and that leaves our friends in Beijing holding the bag.
Hannah suspected this Mendes, once he had been spotted and knew it, had flown the coop.
The other was empty and it was empty because Ray Booth, he of the purple LSU fraternity ring, had flown the coop.
Hey, if he had anything to do with this, he would have found out that you'd flown the coop.
He opened it and read: Brothers Katzen-jammer have flown the coop.