These covered hog and sheep pens stretch south from E. Exchange Avenue to Marine Creek, and were used to hold livestock during auction and prior to being slaughtered at the packing houses just to the east. In 1911 they were modernized and rebuilt at a cost of $150,000. Concrete posts, roof, firewall, and brick paving were used in order to fireproof the structure and in the interest of hygiene. Underground tunnels and ramps to the packinghouse and extensive sewers were installed before construction of the pens. Now vacant and closed off from the public walkways with chain link fences, the pens remain a tangible vestige of the vast scale of the stockyards operations. They are within the boundaries of the Fort Worth Stockyards National Register Historic District.
