The farmers are bringing in the harvest faster than it than the mill can accept it. They are piling it on the ground near the bins and processing it at night. The weather has been terrible for the harvest this year, almost t continuous rain.
Sparrows etc don’t go near the pile. As soon as it is cleared the will go and root around in the gravel to find seeds. Perhaps so much food overwhelms the birds to the point they don’t recognize it as a food source.