My wife's aunt passed away awhile back. I don't think she ever threw anything away. Her father was a farmer and teacher. I found some interesting articles that he had saved and she had kept. One was how to measure hay in the stack. I thought I would pass it along to see if anyone had ever heard of this.
Measure the stack for length, width and over ( to get the over throw a tape line over the stack at an average place from the ground to the ground, drawing it tightly).
1. Multiply the width by the over and divide this result by four.
2 Multiply the result of division by the length for approximate cubical contents of stack.
3. To reduce to tons for hay that has stood in stacks less than 20 days, divide cubical contents by 512; for more than 20 days and less than 60 days divide cubical contents by 422; for more than 60 days divide cubical contents by 380.
He had handwritten another formula on the back of the article to get the cubic feet but it's so faded I can't make it out.

we measured hay very much like that I don't remember exactly bought and sold hay by measure. We would buy staked hay pitch it through a small square baler bought it for 30-35 a ton sold for 80 A ton some was sold by the bale. had a trucker that would come 3 times a week if we had a load for him he hauled 18 ton. we bought and sol 350-6oo ton a year for 10 years.

And I'll bet he did all the calculating in his head! People used their brains far more than they do today when we rely so much on gadgetry.

The usda crop adjuster did not have this formula in his book so he could not use the one I forgot his

Yes, my father used to do this.. I sure don't remember the formula, but it was agreed on by all.. I have a small booklet that shows a lot of these old formulas… one time we had a piled of rye on the ground and wanted to see how much we had as the local feed company wanted to buy it.. we tried to find and eventually did find a formula to measure this and convert it to bushels.. had to call my old school teacher and she had to go back thru' some old books to find what we needed…

It is all simple mathematics. Nothing at all magical. Go back and break it down into a basic geometric shape. The 512-422-380 are adjustment numbers that account for settlement.

Mathematicians (and engineers) like to make it complicated enough to fool the masses. It ain't rocket science.

https://www.ag.ndsu.edu/pubs/ansci/livestoc/as1282.pdf