My chickens did that all the time before they would lay an egg when they started. They would start going in and out and scratching all the time. few days later.. our first egg! When your chickens are laying they will be doing that every day.
X2, it is not unusual for pullets especially to do this for days before they lay an egg. Sometimes even when they are going to lay an egg they will first check out every nest box on the place until they decide which one is perfect.