In railroad terminology, a stock car or cattle car is a type of rolling stock used for carrying livestock (not carcasses) to market. A traditional stock car resembles a boxcar with louvered instead of solid car sides (and sometimes ends) for the purpose of providing ventilation; stock cars can be single-level for large animals such as cattle or horses, or they can have two or three levels for smaller animals such as sheep, pigs, and poultry. Specialized types of stock cars have been built to haul live fish and shellfish and circus animals such as camels and elephants. Until the 1880s, when the Mather Stock Car Company and others introduced "more humane" stock cars, death rates could be quite high as the animals were hauled over long distances. Improved technology and faster shipping times have greatly reduced deaths. Initial use and development Rail cars have been used to transport livestock since the 1830s. The first shipments in the United States were made via the Baltimore and Ohio Railroad in general purpose, open-topped cars with semi-open sides. Thereafter, and until 1860, the majority of shipments were made in conventional boxcars that had been fitted with open-structured iron-barred doors for ventilation. Some railroads constructed "combination" cars that could be utilized for carrying both live animals as well as conventional freight loads. Getting food animals to market required herds to be driven hundreds of miles to railheads in the Midwest, where they were loaded into stock cars and transported eastward to regional processing centers. Driving cattle across the plains led to tremendous weight loss, and a number of animals were typically lost along the way. Upon arrival at the local processing plant, livestock were either slaughtered by wholesalers and delivered fresh to nearby butcher shops for retail sale, smoked, or packed for shipment in barrels of salt. The suffering of animals in transit as a result of hunger, thirst, and injury, was considered by many to be inherent to the shipping process, as was the loss in weight during shipment. A certain percentage of animal deaths on the way to market was even considered normal (6% for cattle and 9% for sheep on average, according to a congressional inquiry), and carcasses of dead animals were often disposed of along the tracks to be devoured by scavengers, though some were sold to glue factories or unscrupulous butchers. Increased train speeds reduced overall transit times,