Bougyaku no Kokekko

Bougyaku no Kokekko manga summary: Meet Yuu Enji, a boy abandoned by his father, and the oldest kid in his foster home who's fed up with adults like his selfish orphanage principal. His dream is to buy the orphanage, so that everyone there can live happily together. With that goal in mind, he decided to get a job, and went to his high school graduation. But from that day forward, the world suddenly changed! Adults have now started to morph into giant chickens and attack children! Can Yuu protect the children and his dreams during this crisis!?