IF your information is correct then it is a one time thing. POSSIBLY because of the number of foreign horses which might still be harboring some unacceptable virus or bacteria which would not be acceptable to process and then spread as fertilizer or use as compost??? Just a thought.
Usually manure from the horse park is processed and recycled. I had heard that the processing center was right on the property, although memory might not serve me right. It has happened before. 
Rest assured, recycling manure is part of the nature of farming in Ky – Many/most big farms create manure piles which are spread on their own fields as fertilizer.
Having moved from Lexington, I am still a “straw bedding person” and I still spread manure on my fields.
Another misconception from above: Creech does not GIVE away their compost. They have contracts with (at least in the past) Campbells, Vlasic, etc. and sell it as organic fertilizer which did go to mushroom farms in the upper midwest.
It used to be free to dump there since Creech was making its money on the back end, but they became overwhelmed with manure, so they started charging in the mid - 90’s.