It happened to KFC, and it happened to In-N-Out Burger. Now, it's happened to Chick-fil-A.

Becuse while Amazon can do away with cashiers, and Starbucks can do away with cash--and even McDonald's can try doing away with the American rite of passage of working at McDonald's--there's one thing that restaurants absolutely, positively cannot do without.

At two Chick-fil-A restaurants this past week, a key ingredient was apparently missing: chicken.

"Chick-fil-A temporarily closed two restaurants in Texas this week due to an issue with one of its suppliers," Business Insider reported. "The problem left the restaurants without any chicken -- the main ingredient in most of Chick-fil-A's dishes -- to serve customers, according to a Facebook post from one of the closed locations."

"Delivery delays are common"

That Facebook post reported, "Due to a vendor error that caused us to have a lack of chicken products delivered today we chose to close for the day."

Of course, this is nowhere near the problem KFC faced earlier this year, when it had to close down almost all of its restaurants across the UK due to a temporary chicken shortage (which led to one of the all-time cheeky great corporate apologies).

Separately, In N Out shut down in Texas for lack of quality hamburger buns. (Whataburger made a point of staying open and offering wheat replacement buns, when faced with the same issue.)

But, this recurring story comes along as the media has begun to pay attention to another shortage--the fact that the nation's transportation companies are suffering from a severe lack of qualified truck drivers.

There are 63,000 open truck driving positions in America--a figure expected to double shortly--and some of the jobs offer brand new drivers $70,000 a year, the The Washington Post reported recently.  "Nearly every item sold in the United States touches a truck at some point. ... Already, delivery delays are common."

In other words: No truck drivers, no trucks. No trucks, no deliveries. No deliveries--maybe, no fast food.

Hey, here's a solution

Granted, I don't know if a lack of drivers led to a lack of chicken here. I'm offering these two stories together as a possible harbinger of challenges to come. I asked Chick-fil-A for comment, but I have yet to hear back.

But if you're running a business--whether it's an $8 billion a year company like Chick-fil-A or something much smaller--and if you depend on suppliers to keep your doors open, what do you do?

Build redundancy into your processes, I suppose. And pray for the promised arrival of self-driving vehicles.