Just came up in random conversation with partner and meant to bring this up months ago. We buy in ewe lambs, lamb them and sell as shearlings, so basically we have a new flock each year. A while back we were looking at an aerial photo taken of farmhouse and included about 80 acres of our fields. Was taken late 1980s. Then for some reason was looking on google earth maps and viewed the same shot but taken in 2015. We grow 3 crops of corn and then a grass ley for 7 years, In between these 2 photos the field has been ploughed and worked down 9 times. One field in photo is 45 acres and has 2 water troughs either end of the field. The tracks to these troughs made by the sheep following eachother on the 2 different pictures is exactly the same , literally to the same inch. Whether air currents dictates this or what i dont know. As said buy in new sheep each year, dont keep lambs from them so not in any way like hefted sheep. Land being worked down that often i doubt there is a firmness to tracks that dictates them taking that route, and sure as hell not any firmness in field this winter!! Last 150 metres before one tank is on a 60ft bank and they go to tank in a semi circle going up around 45 degrees. So not direct route. Nothing earth shattering i admit, but just found interesting