I was kind of in a sticky situation when my girls started laying. They were living on the screened porch in a pen almost as big as the porch itself!
The coop building kept getting delayed due to health issues and weather.
One day (@ 19 weeks) when I noticed one of my girls refusing to leave the porch with the others and instead checking out every container - flower pots, boxes, etc. - on the porch I knew I was in trouble.
You should have seen me trying to convince her that a canvas lounge chair on the porch was indeed the perfect place for a girl to lay her first egg. After that first day she dutifully went straight to her chair each day.
Then when we did finally get them moved to the coop, I had to break her from going to her chair on the porch each day!
I spent alot of time praying that none of her sisters would start, because we only had two chairs!
So unlike everyone else on the forum, I really REALLY didn't want early layers.