Hen hogging the nesting box

[Slotred]

My hen house is small (4x4x4), but it has been adequate for my four six-month old australorp girls. Now, one of them is hogging the nesting box, forcing the smallest one, and maybe others, to lay her daily egg on the floor. Sometimes the egg breaks, and we have a mess. I tried adding an additional nesting box, but everyone seems to want the same box. Any suggestions?
Thanks.

 

[Ridgerunner]

Where does she spend her nights, on the nest or on the roost? If she is staying on the nest at night, she is broody. If she is broody, you can either give her fertile eggs or break her from being broody. To break her, you might find this helpful. I prefer the wire bottomed cage method.

Break a Broody Thread
https://www.backyardchickens.com/forum/viewtopic.php?pid=2176186#p2176186

If you give her fertile eggs, with your set-up I'd suggest finding a way to lock her in a separate nest where she can't get out and the others can't get in. It needs to be predator proof, of course, and she needs room for food, water, and enough room to poop without messing up her nest.

If she really is broody and you need more help, just ask.

Have you tried putting a fake egg in the second nest box?