How to raise Backyard Chickens: [CHICKENS-101] Newbie question: Chickens getting out of the yard?

Hello,

Fall is fast approaching- I'm about to build a coop and will have some hens by the end of October.

My concern is that my home borders a 'common' grassy area in my community. My back south-facing wall is about 5ft brick with an additional 1.5ft metal gate on top. A friend who'd once raised hens visited me recently, and told me that if I let my chickens out of their run(which I plan on doing daily) that I should plan for them getting over my back fence.

If that's true,.. I can't think of any way to prevent them from getting up on the brick wall and scrambling over the fence. I suspect they'd return at some point... but I'm concerned that they might split for large portions of the day and be in danger from other animals or neighbors, get lost, etc.

Do chickens generally stay in a yard, only to hop such a fence sporadically?

Or is it common for them to go out exploring on a daily basis and get
into trouble?

Does anyone have any tricks or tips on ways to train/bribe them to reliably stay in the yard? Maybe some simple modification to my fence to train them away from it? (no electricity or spikes, lol)

Any guidance or help would be much appreciated!

Thanks,
Tom