With 11 girls that are all only 6.5 months old, I get the occasional early egg (before 9am). Generally though, they lay between 10am and 4pm eastern. I also get the occasional 5-7pm egg, but that is even more rare than the early morning egg. My chickens' eggs and places of lay are all different, so I know pretty much who laid which egg and at what time.
They do gravitate as a flock towards later in the day for some reason, and then gravitate back to earlier in the morning. Since they are all the same age and all confined together and all exposed to the same environment, food, etc., I attribute their collaborative egg laying time to the environment more than anything else.
Sometimes I disrupt their egg laying times (or the times for some of them) when I go into the hen house and see that the feeder needs to be refilled. If anyone is in the box when I refill the feeder, she will typically jump out of the box to eat, delaying her egg for a few hours after that.