All our chickies are using the same laying box

[Ol Grey Mare]

Sorry we dont have a solution for you, seems you are not alone though!

The reason there isn't a "solution" is that there isn't actually a problem - this is natural chicken behavior and is actually indicative of happy, healthy birds doing what comes naturally to them - something to be embraced rather than fixed.

 

[SIERRAS MOM]

Just block off the favorite nest for a while and make them move over to the other nests. It actually is not a very good habit because to many eggs together can get broken then they start the very bad, never break habit of eating their own eggs.