Hemp is being grown commercially again in Canada. Harvested for the long slender fibres on the outside of the stalk, it is used for applications in textiles, composites and paper. The core of the stalk is used for animal bedding, garden mulch and building materials. Hemp is an annual plant that grows from seed. They are not palatable to horses due to their limited nutrient content.
Wet areas tend to be smaller and noticeable less often.
Remove the manure daily, digging out the wet spots as required. You will find that a much smaller manure pile is produced due to the reduced material being removed in comparison to other bedding products.