Dawn,
Your email brought back a ton of memories.  The nickname came from the fact that the 727's were poor climbers so we called the pigs.  Over time, a bunch of names were applied to every one of the 727 fleet.  I loved the names pilots came up with for the planes.  One of my favorites was: N54348 -231(A) My Hammy Vice.  A few of the pilots got stickers printed and at one time or another you would find a sticker applied to the plane, sometimes right at the entry door.  The newer -231 727's were the really slower climbers.  The -31 & -231 were the numbers that Boeing gave to the TWA planes.  The TWA 707's had a similar # -331, 331B, 331BA etc.

Of the 90 something 727s TWA operated, these are some of the names...

Registration - Type - Name
N12301 -231 Porky's Flagship
N12302 -231 Porky's Petunia
N12303 -231 Hambone
N12304 -231 Porc du Jour
N12305 -231 Picnic Ham
N12306 -231 Heavenly Hambone
N12307 -231 Pigadilly
N12308 -231 Duroc Delight
N52309 -231 Sows About It
N52310 -231 Squealor Pealor
N52311 -231 Spring Chitlin
N52312 -231 Lard Sakes
N52313 -231 Kermit's Desire
N94314 -231 Hampshire Humper
N64315 -231 Hog Lander
N44316 -231 Trough Aloft
N74317 -231 Weiner Winger
N74318 -231 Pigmalion
N64319 -231 Aurora Boarialis
N64320 -231 Lard Above
N64321 -231 Heavenly Hog
N64322 -231 Ham Sweet Ham
N64323 -231 Petulant Porker
N64324 -231 Gilty Lady
N54325 -231 South Dakota Suey
N54326 -231 Me-a-Farrow
N54327 -231 Poland China Diner
N54329 -231 Makin' Bacon
N54330 -231 Short Lardage
N54331 -231 Smokin' Porkin'
N54332 -231 Porky's Palace
N54333 -231 Pig o' my Heart
N54334 -231 Truffle Hunter
N54335 -231 Strato Swine
N54336 -231 Fog Hog
N54337 -231 Oklahoma Oinker
N54338 -231(A) Pickled Pig's Feet
N64339 -231(A) Star Swine of Beirut
N54340 -231(A) Bacon Bomber
N54341 -231(A) Gloria Vandergilt
N54342 -231(A) City of Smithfield
N24343 -231(A) Boaring Soaring
N54344 -231(A) Old Lang Swine
N54345 -231(A) Pork Link Connected
N64346 -231(A) Sue Oui
N64347 -231(A) Road Hog
N54348 -231(A) My Hammy Vice
N54349 -231(A) Sty Stream
N54350 -231(A) Sow Belly
N54351 -231(A) Ozone Oinker
N54352 -231(A) Ham Commander
N54353 -231(A) Poland China Clipper
N54354 -231(A) Millenium Wallflower
N84355 -231(A) Porker Forker
N84356 -231(A) San Juan Sow
N84357 -231(A) Barbados Bristler
N831TW -31 Boeing Oink
N833TW -31 Ham Tram
N839TW -31 Piggy Sue
N840TW -31 Sky Pig
N841TW -31 Thunder Pig
N842TW -31 Porky's Pride
N844TW -31 Pork Chop
N845TW -31 Warped Hog
N846TW -31 Lil' Porky
N847TW -31 Schwine Der Blitzen
N848TW -31 Hog Jaw
N849TW -31 Lard Limo
N850TW -31 Jimmy Dean
N851TW -31 Short Snort
N852TW -31 Queen of the Sty
N853TW -31 Kitty Hog
N854TW -31 Cloud Boarer
N855TW -31 Slow Pork
N856TW -31 Porcine Princess
N857TW -31 Swine Flew
N859TW -31 Gloria DeJavaline
N889TW -31 Celestial Chitlin