I was thinking of using golf balls cause that's what I have currently and fake eggs are out of our budget at the moment. As far as fake eggs go, do I always leave them in the nest boxes or can I take them out after they learn where to lay? Haven't seen that mentioned anywhere.
I use golf balls.
They do no harm, may help, and are easy to tell from actual eggs by touch when you're reaching under a hen to get the eggs out of the nest.