Horse manure is perhaps the most easily available manure type in the UK. Generally It is mixed up with hay, [[wood chippings}} or sawdust, as sweepings from stable floors. Its is generally dried out so easier to handle. It tends to contain seeds, that often go undigested, which may cause weeds in gardening. An average adult riding horse (weighing approximately 900 - 1,100 pounds) produces around 8 to 9 tons (16,000 and 18,000 pounds)of manure every year.