The Collaborative International Dictionary of English v.0.48:

Biddy \Bid"dy\, n. [Etymology uncertain.]
   A name used in calling a hen or chicken. --Shak.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Biddy \Bid"dy\, n. [A familiar form of Bridget.]
   An Irish serving woman or girl. [Colloq.]
   [1913 Webster]

WordNet (r) 3.0 (2006):

biddy
    n 1: adult female chicken [syn: hen, biddy]
    2: young bird especially of domestic fowl [syn: chick,
       biddy]

Moby Thesaurus II by Grady Ward, 1.0:

121 Moby Thesaurus words for "biddy":
   Bantam, Jane, Partlet, abigail, amah, au pair girl, ayah, bag,
   banty, barn-door fowl, barnyard fowl, bat, beldam, betweenmaid,
   bird, bitch, bossy, broad, broiler, brood mare, brooder,
   broody hen, capon, chambermaid, chanticleer, chaperon, chick,
   chickabiddy, chicken, chicky, cock, cockerel, companion, cook, cow,
   crone, dame, doe, doll, domestic fowl, drab, drake, duck, duckling,
   duenna, dunghill fowl, ewe, ewe lamb, femme de chambre,
   fille de chambre, filly, fowl, fryer, game fowl, gander,
   gentlewoman, girl, gobbler, goose, gosling, guinea cock,
   guinea fowl, guinea hen, gyp, handmaid, handmaiden, heifer, hen,
   hen turkey, hind, hired girl, housemaid, jenny, kitchenmaid,
   lady-help, lady-in-waiting, lioness, live-in maid, live-out maid,
   maid, maidservant, mare, minx, nanny, nanny goat, nursemaid,
   parlormaid, partlet, peahen, poulard, poult, poultry, pullet,
   roaster, roe, rooster, scullery maid, servant girl, servitress,
   setting hen, she-bear, she-goat, she-lion, skirt, slut, soubrette,
   sow, spring chicken, stewing chicken, tigress, tom, tom turkey,
   tomato, trot, turkey, turkey gobbler, upstairs maid, vixen,
   waiting maid, wench, witch