The grass is knee height mostly and the land like the sea when the wind changes, wavy in bigger wave in bigger wave - undulations in larger undulations in larger undulations which are in low 8/9 foot hills which form part of the bigger coastal hills. In the lower drop outs the grass grows taller to level with surroundings, so although that picture is relatively flat, the ground level is a foot or two different different just a few meters in any direction. If a pig drops it is very unlikely you will see it from even 30 meters away. If it drops and gets up while eyes are off spot it can disappear in a blink.
IMG-20220109-WA0074 by David Frank Allen, on Flickr

All photos were taken in grazed areas where grass was short, we had to drive or drag to photo spots.