How do you teach chooks to lay their eggs in a laying box?

[kiwifoster]

My 3 chooks are 25 weeks old and should be starting to lay soon. we have had them since they were 14 weeks old. There is one each of Black Australorp, White Leghorn and a Rhode Island Red.
My question is, how do you teach them to lay the eggs in a laying bax or do they do this instictively?
Other chooks I have had have been older and laying when I got them and they just went straight into the laying box.

 

[JulieNKC]

If you leave a fake egg or golf ball in the boxes they will be more likely to lay in them.

 

[OkChickens]

I put a golf ball in there nest boxes for 2 reasons.

1st to show them this is a good safe place to lay there eggs.
2nd for a snakes. They will only eat one and they pay the price for trying to steal an egg!

I have 1 EE hen with my 20 5 month old pullets (10 RIR and 10 Barred Rocks) and they just figured it out. They started to lay right at 6 months. Every once and a while I will find a clutch of eggs on the ground in a corner with a nest of hay but that hardly happens. Now they are right under 7 months old and I get on average 28-30 eggs a day from my 34 hens I let my 35 chickens (1 Roo) free range all day everyday! I get at least 1-2 double yolkers a day from my pullets! Congrats! I hope they start laying soon!

Nate