Up or down?

It's easy to imagine this is a view up a chimney or a shaft but it's actually a chute, one of several set into our farmyard wall, leading to slate troughs below. It's an unusual feature that dates from the days when the pigs ranged free and were supplied with slops (the lees from brewing beer or the surplus buttermilk) poured down these chutes thus saving  your feet getting wet or your legs nibbled at close quarters.
I've never seen the like and would guess it dates way back into the past.

Extra shows the row of troughs on the other side of the wall.

Two snails kindly agreed to remain in situ to demonstrate the scale.