Will my chickens eventually use the nesting boxes?

[Farmer Mike S]

This is my bad because I opened the boxes up 3 days ago which is late and I got my first egg today. The chickens are somewhere between 21-23 weeks old. Anyway, my first egg was laid in this corner:

And here's my nesting boxes:

The actual opening with the board in front is 10 inches, but from the bottom to top it's 14 inches tall in front and 12 inches tall in the back. They are also 12 inches deep and 12 inches wide.

I just want some advice

 

[Chicks and Hens]

Put maybe a golfing ball to show them where to go in one of the nesting boxes and give them some privacy some chickens like not being seen while they are doing their "buisness"