3 Pa. Stat. § 84
Whenever unmanufactured horse manure is furnished, sold, or delivered in this Commonwealth, such manure shall be only the natural product as the same is produced by horses in the stable, together with the straw bedding, without the intentional addition of water, any other manure, or any other foreign substance whatsoever. For the purposes of this act, unmanufactured horse manure shall be deemed to be adulterated if it contains any water, intentionally or deliberately added, or if any other manure, or any other foreign substance is intentionally mixed therewith, whether such added water, manure, or other substance is added thereto, or becomes a part thereof, by permitting water or any other substance to flow or seep into, or otherwise become a part of such unmanufactured horse manure while standing in a manure pit or any other place.
3 P.S. § 84