The Collaborative International Dictionary of English v.0.48:

packinghouse \packinghouse\ n.
   1. A place where foodstuffs are processed and packed; as,
      they came from an apple packinghouse.
      [WordNet 1.5]

   2. A plant where livestock are slaughtered and processed and
      packed as meat products.

   Syn: packing plant.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

packinghouse
    n 1: a building where foodstuffs are processed and packed; "they
         came from an apple packinghouse"
    2: a plant where livestock are slaughtered and processed and
       packed as meat products [syn: packinghouse, packing
       plant]