Easter egg: In the main menu, on "play movie", press the numbers 09-23 on the remote as a short cut to other Arrdman classics.
Easter egg: There are about a dozen chicken eggs throughout the menu and each one gives interesting facts about production. Also, the panic button in the main menu activates one of two clips showing panic in the coop.
Chosen answer: Because he wanted them all to have something to look forward to, he didn't want to let them down. Plus Rocky is very bigheaded, it would no doubt be embarrassing for him to admit that he couldn't fly.
THGhost