The Collaborative International Dictionary of English v.0.48:

Frier \Fri"er\, n.
   1. One who fries.
      [1913 Webster]

   2. same as fryer.
      [PJC]

WordNet (r) 3.0 (2006):

frier
    n 1: flesh of a medium-sized young chicken suitable for frying
         [syn: fryer, frier, pullet]