On the Raby estate, all buildings on land belonging to the estate have to be painted white.
Agricultural buildings have to look 'weathered', so, after repainting (or building), they get sprayed with a very dilute solution of water, yoghurt and slurry.
This dates back to some lord, who, lost in a terrible storm, saw a light. A farmhouse! Threw the door open, staggered in, demanded food etc.
The farmer, who happened to own his farm (rather than being one of the lord's tenants), told him where to go.
In a rage, the landlord declared that henceforth, all of the buildings on his land would be painted white (so he could easily identify them).