5pm!! That's a record! I think we had one laid as late as 4:30pm, and that's when she just started laying.
We installed a baby monitor so we can see if someone is in the nesting box, and it becomes quite fun to "spy" on them! We are also lucky that each of them has a distinct signature color/shape/size. So I can always tell whose egg that's there! We have two EE, and even they have different shades of blue and sizes.
They are also easily distracted - so I tried not to go into the run (connected to the coop) if someone is in the nesting box. Every once in a while, they are all in sync for early morning "homework". Yesterday for example, there was quite a traffic jam in nesting boxes. One box had two birds in there, one sat sideway in the back!