When to move the cows?

Last weekend we went to check on a group of cows.  This group of cows were grazing in a part of the country that has been seen only by a few humans.  To get to this pasture you have to go on foot, horse or ATV.  Since we don't have horses and the idea of walking in deep snow or mud for miles is unappealing, Jake uses an ATV. In this particular field it is difficult to navigate even by ATV.  Jake says it is extremely rocky, rough and steep.  However wants you get through that, there is a fabulous pasture with ample grass.  Cows do not seem to mind the walk and do so willingly.  The downside is they also come out on their own time.  Jake says you can't drive or call them down and they will only come out to the bottom ground when they have eaten the grass they have up there. That seems logical for a cows mind.  We went to check on them to see if they were ready to move to another pasture last weekend after the snow.

Guess what? No cows.  Cows are smart creatures, it was snowing and about 20 degrees, they had food and were staying put.

This is one of the bridges on the way to the pasture.
Cows do not generally go over bridges and would rather pass through the water than use the bridge.

This is the other option.
This may be why they were still grazing and not wanting to move to  another pasture.

 The snow has melted and the cows suddenly appeared in the bottom ready to move two days later after the snow had melted and temperatures were pushing 70 degrees on Tuesday.

They came back to the bottom ground and were ready to move, no coincidence that is a lovely sunny day.

All of them go into the water, not one chose the bridge.

It looks like Lonesome Dove, only this is not the Platte River and Jake didn't go across  by way of water and horse.

They all reached the other side.

They move on to more grass and other pastures.

The answer to the question. When to move the cows? When they are good and ready.