The Collaborative International Dictionary of English v.0.48:

Heeler \Heel"er\, n.
   1. A cock that strikes well with his heels or spurs.
      [1913 Webster]

   2. A dependent and subservient hanger-on of a political
      patron. [Political Cant, U. S.]
      [1913 Webster]

            The army of hungry heelers who do their bidding.
                                                  --The Century.
      [1913 Webster]