The Collaborative International Dictionary of English v.0.48:

Chicken \Chick"en\, n. [AS. cicen, cyceun, dim. of coc cock;
   akin to LG. kiken, k["u]ken, D. Kieken, kuiken, G.
   k["u]chkein. See Cock the animal.]
   1. A young bird or fowl, esp. a young barnyard fowl.
      [1913 Webster]

   2. A young person; a child; esp. a young woman; a maiden;
      same as spring chicken. "Stella is no chicken." --Swift.
      [1913 Webster]

   Chicken cholera, a contagious disease of fowls; -- so
      called because first studied during the prevalence of a
      cholera epidemic in France. It has no resemblance to true
      cholera.
      [1913 Webster]

WordNet (r) 3.0 (2006):

spring chicken
    n 1: a young person (especially a young man or boy) [syn: young
         person, youth, younker, spring chicken]
    2: a young chicken having tender meat