I have seven 6 months old Barred Rocks.
There are 3 nests. Each have a ceramic egg. They do have a favorite where most eggs are laid.
Yesterday around 9 am I went to collect eggs and give them a daily treat of Scratch scattered around the pen.
I collected two eggs from the favorite nest.
After they finished the Scratch, 3 pullets went into coop to lay. Of course they all want the favorite nest.
One went into nest and another went in and pushed the other out. This went back and forth, pushing and shoving, going into another nest squawking, coming out and squawking at the pullet in the favorite box.
I watched them for 15/20 minutes and they continued squawking. I left them to figure it out and cook up some eggs for breakfast.
Later in the day I went to the coop and the favorite nest had 2 eggs and another nest had 1.

I may never figure out what makes one nest box so desirable. But that's what makes chickens so addicting. Trying to figure them out. What is that chicken thinking? GC