On arriving at the checkout there will often be someone in front of you. If there isn't then you can breeze on through and try an alternative game such as Checkout Chatter. Anyway, for Checkout Chicken it is imperative to have someone in front with goods on the conveyer belt. It's even better if they have someone with them as that person will be doing the packing and therefore the first person can only stand around and wait to pay.
Normally on arriving at the checkout and finding someone else's goods in front, it is deemed good manners to place the little divider thing at the back of their goods. This then allows the checkout operator with a means by which to discriminate between the goods of the two purchasers. However, with Checkout Chicken, you must avoid placing the divider in between their goods and yours. You should just start unpiling your goods onto the conveyor belt.
As time passes and tension builds, your goods edge closer to the cashier, you start to believe that your goods are about to become part of those of the person in front, and that you are about to cause untold chaos and havoc at the checkout. In the meantime, the person in front may have noticed that there is no divider and will begin to become quite worried too.
To win at Checkout Chicken you just have to be the one who does not put the divider thing on the conveyor belt. Sometimes the person in front just plain and simple doesn't notice, which means you're playing on your own and cannot conceivably win. Unless you're a hardened player this'll certainly screw your nerves up. Other times, your 'opponent' will dive straight in there and you'll get an easy win. On rare occasions you both keep your nerve and they end up buying half your stuff, although not necessarily for you!
The best part about 'checkout chicken' is you get to play twice on every trip, once with the person in front and once with the person behind. An opportunity for instant redemption should you have failed on your first try.