The Power of the Fake Egg
One thing you will learn when raising chickens and ducks is that they may not always like to lay where you want them to. Chickens and ducks tend to lay where the others are laying, you will find this annoying when 5 chickens will be fighting over 1 nest box when there are 6 more to choose from.
One thing you can do is to add in fake eggs to the mix. By placing fake eggs in your nesting boxes, you can encourage the fowl to lay where you want them too. This can be done, not only when your hens first starting laying, but regularly. We leave some fake eggs in the coop permanently to encourage the chickens to spread out and not use just the one box.
I would suggest marking the eggs with an "X" to keep from handing out fake eggs to your clients.
Also, chickens can tell the difference in weight and texture. Those little plastic eggs don't tend to work, so I would get either the wooden eggs or hard ceramic. You can buy these at a farming store for $4 for 2 eggs, or you can look in the toy department and find some for a bit cheaper or wait until easter.