The Collaborative International Dictionary of English v.0.48:

Fowl \Fowl\ (foul), n.

   Note: Instead of the pl. Fowls the singular is often used
         collectively. [OE. foul, fowel, foghel, fuhel, fugel,
         AS. fugol; akin to OS. fugal D. & G. vogel, OHG. fogal,
         Icel. & Dan. fugl, Sw. fogel, f[*a]gel, Goth. fugls; of
         unknown origin, possibly by loss of l, from the root of
         E. fly, or akin to E. fox, as being a tailed animal.]
   1. Any bird; esp., any large edible bird.
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            Let them have dominion over the fish of the sea, and
            over the fowl of the air.             --Gen. i. 26.
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            Behold the fowls of the air; for they sow not.
                                                  --Matt. vi.
                                                  26.
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            Like a flight of fowl
            Scattered by winds and high tempestuous gusts.
                                                  --Shak.
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   2. Any domesticated bird used as food, as a hen, turkey,
      duck; in a more restricted sense, the common domestic cock
      or hen (Gallus domesticus).
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   Barndoor fowl, or Barnyard fowl, a fowl that frequents
      the barnyard; the common domestic cock or hen.
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