The Collaborative International Dictionary of English v.0.48:

Ball \Ball\, v. i. [imp. & p. p. Balled (b[add]ld); p. pr. &
   vb. n. Balling.]
   To gather balls which cling to the feet, as of damp snow or
   clay; to gather into balls; as, the horse balls; the snow
   balls.
   [1913 Webster]