In chapter eight, "Gift for the Darkness," Jack finally splits from Ralph's tribe with a petulant "I'm not playing any longer. Not with you" (127). While Ralph is visibly shaken by Jack's departure, Piggy is estatic. Jack never respected him, shoved him and broke his glasses, and belittled him with rude names whenever possible, so Piggy is not the least bit disappointed to see Jack Merridew leave the tribe.
Piggy's new found enthusiasm at Jack's leaving translates into a more hands-on approach at the camp as well. Even with his asthma, Piggy pitches in to help build the new fire and gather fruit with Samneric:
"Piggy was so full of delight and expanding liberty in Jack's departure, so full of pride in his contribution to the good of society, that he helped to fetch wood" (129).
Part of Piggy's perky attitude is motivated by a desire to cheer up Ralph, who is still rather down-trodden and depressed about the tribe splitting up. Piggy uses the sudden shift in politics to establish a new working order in the tribe, one without Jack Merridew, where he can play a more prominent role as Ralph's second-in command.