WHY DO PEOPLE alwyas say, 'get your ducks in a row"?!?!!?

When ducks are in a row, it's easier to bowl them over with a bowling ball.

Observe how ducks travel. They move "in a row", not stacked or otherwise. That's why this expression means orderly.

to prepare something carefully so that you make no mistakes

https://www.macmillandictionary.com/dictionary/ame...

http://www.worldwidewords.org/qa/qa-duc5.htm

to be well prepared or well organized for something that is going to happen:

https://dictionary.cambridge.org/dictionary/englis...

https://idioms.thefreedictionary.com/get+ducks+in+...

V formation is more likely. I'd want my ducks in a tight flying V formation with excellent wing-ducks.

Even the possible origin of bowling ducks suggests V formation.

Have you ever tried to stack ducks?

Good air traffic control procedure to have them lined up in a row.

Very pretty when the ducks turn their landing lights on - the classic "string of pearls".

Stack up traffic only when you must: vertical spacing is terrible for fuel economy. Even if you're a duck.

Challenge accepted, lets just SEE how you would stack several ducks?

I would guess (in fact I'd bet money) that this comes from old-fashioned shooting galleries where animated ducks move across the target in a row. If you're set up right you can shoot them in order as they cross the point where you're aiming. This is a luxury real duck-hunters don't have.

It certainly would be cooler, and more impressive, to have them stacked on top of each other! But real ducks don't do that, and it would be useless in a shooting gallery.