Actually I have been using golf balls... mostly because the wooden eggs keep disappearing. The first time I found them halfway to the creek with scratches on them . Also when dirty they look like dirty eggs. I found that out when I washed one to cookYep. My local Fleet store only sells the ceramic eggs, and they are about $3.00 each. Amazon was selling colored wooden eggs for about $1.00 each. It's probably a once in lifetime purchase, either way, but I wanted to save some money. I think having fake eggs in the nest box does encourage the hens to keep laying in the next box. For me, it was a good purchase.

I also use dated real turkey eggs because my turkeys can tell the difference. Turkey eggs are harder to get broken.
I bought some fillable easter eggs last year on clearance. I filled with sand and taped close. 2 and a golf ball are missing from nesting places in poultry yard. 2 were broken open in the coops and no one is using the boxes that still have them.