I don't think he was talking about cows standing on concrete all day, just pouring a pad for feeding hay. Like you sketched earlier, to keep cows and hay out of the mud, just when eating hay, over the winter.

Also suggested was using electric fencing to limit the number of hours a day that cows can get to the hay.  He was really down on folks having hay available to cows "24/7".

I am thinking of a hay "shed" as you sketched but without a roof. A pad with posts and guard rails but no roof. I don't want them getting used to having a roof  over their heads and parking under it for much of the day. They can come to it to feed  but then go back to the woods for shelter.

This will not be for storing hay, just feeding it.

Still in the thinking stage.

Jim