The Collaborative International Dictionary of English v.0.48:

Pig \Pig\, v. t. & i. [imp. & p. p. Pigged; p. pr. & vb. n.
   Pigging.]
   1. To bring forth (pigs); to bring forth in the manner of
      pigs; to farrow.
      [1913 Webster]

   2. To huddle or lie together like pigs, in one bed.
      [1913 Webster]