Those dreaded words, "Final Weeks," have begun cropping up in ads for When Pigs Fly, the hit Off-Broadway musical created and designed by the late Howard Crabtree.

That means the show could run a couple of weeks or keep going indefinitely, depending on how ticket sales go. "There's no closing notice posted yet," spokesperson Tony Origlio told Playbill On-Line, "so we'll see what happens. There's a lot of springtime competition out there."

The hope is that Pigs will at least make it to Aug. 14 -- its second anniversary at the Douglas Fairbanks Theatre.

The revue gives its 721st performance May 4.

Crabtree, creator of the critically acclaimed revue Whoop-Dee-Doo!, passed away five days after having completed work on When Pigs Fly, which holds true to his penchant for outlandish and elaborate costumes. Crabtree's long-time collaborator and confidant, Mark Waldrop, has said, "Howard Crabtree's When Pigs Fly really is the show that Howard always wanted to do. Against all odds he finished the costumes for it just before he died -- and they were his his best, funniest, most sophisticated creations ever."

Dedicated to the memory of Crabtree, When Pigs Fly tells the tale of Howard, (a character not unlike Mr. Crabtree), who is in charge of putting together an over-the-top revue but finds himself going over hurdles and combating negative attitudes. The situation is further worsened when his high school guidance counselor keeps popping up to warn him of the pitfalls of the career he's chosen. When asked if she thinks Howard will make good on his theatrical career, she retorts "When Pigs Fly!" The show must go on and it does. And in the end, Howard follows his heart.

Original cast-members David Pevsner, Stanley Bojarski and Michael West (Howard) are still with the show, alongside James Heatherley (who replaced Jay Rogers) and John Wasiniak. Sets and lighting are by Peter Hauser; sound by Rob Gorton.

Pigs won 1997 Outer Critics Circle Awards for Off-Broadway Musical and costume design; Drama Desk Awards for Off-Broadway revue and costume design, a Lucille Lortel Award for costume design, and an all around OBIE.

Howard Crabtree's When Pigs Fly, previewed Aug. 1 and opened Aug. 14, 1996 at the Douglas Fairbanks Theatre (432 W. 42nd St. between 9th and 10th Avenues). For tickets call Tele-Charge at (212) 239-6200.

-- By David Lefkowitz