I've got two hens laying, one started on August 16th and the other on August 19th. The first egg was in the shavings in the floor of the coop, the second was in the sand in the run, the third was in their outer fenced area (their "yard") in the dirt, the fourth was back in the run in the sand, the fifth and sixth and everyone thereafter has been in the nest boxes. We changed nothing. I think on their first couple eggs they were in the next boxes trying to lay but the egg wasn't coming out. Then they would get up and walk around and it would work it's way out. After their first couple eggs they haven't seemed to have issues.
Interestingly, they have two nest boxes to choose from and they are switching back and forth, but both laying the the same on on a given day. Funny birds...