Unless a chicken lays an egg every day of the year it's impossible for them to lay the same time every day.
It may seem like they lay a certain time.
Chickens in their prime are every 26 hours minimum. There are 24 hours in a day. That means they will be a little later each day till they have to skip a day. The next several days the eggs become fully developed at night so they wait till morning to lay them. That goes on for at least the next week after the skipped day.
That makes it seem like they always lay in the morning because most of them are laid in the morning but not all.
In the morning, if treats are being given or some other excitement interrupts them they'll wait longer to lay.
Those of you that let your birds out in the morning and throw scratch, well, they aren't going to stop eating scratch and go lay an egg until after that excitement is over. Those are the ones that seem like they lay around 10 or 11.
Research shows if feed is provided when a hen is about to lay, that will interrupt the cycle.
ETA
Older birds past their prime that don't lay every day will seem like they always lay in the morning and they probably always do.