I have 3 boxes. I have been lucky so far (only 2 laying right now) that they haven't laid anywhere else and just wait for the other one to be done. ONE time I think one couldn't wait so went in the box next to where the other was laying but that was it. the rest you see them come in and out of the coop impatiently waiting for the one in the box to be done or they peek their head in to see if they are still in there and then leave. LOLMine go in first thing to. And they wont lay if another bird is in the box. When there is 2 boxes. And then they will go lay in another spot If they cant get in the nesting box right when they want to.
Poor Annabelle has been in and out starting just after 7 until just after 8 (mostly in) then took a bit of a break and went back again around 8:30. one of the times she spent about a half our wandering around the coop. This last time she walked up to the box that Hummer is in and just stood looking at her. LOL