getting hens to lay in the nest box

If the heat isn't too bad then I'd say go for it. Mine lay in 1 box of the 3 I have. Do you know why???

 

It might help to keep them shut up for a while. I'm surprise that they wait until evening to lay, though. Usually keeping them shut up through morning and afternoon will get them laying in the coop at least.

Some hens just don't like nest boxes, though. I have one EE who insists on laying her egg underneath an old step ladder. It's CLEARLY better than a nice wooden nest box in the coop.

 

I have made nest boxes for mine also, but they have never laid in them. My three hens come and go as they please. They have a nice barn with about 5" of pine shavings. One hen will lay in a corner of the barn with a nest she made herself from the shavings. The other two lay up against the outside wall of another barn (a few feet away) in a nest they made from dirt, old horse manure, grass, etc. One of those hens likes to change her laying spots every now and then. She will hide them somewhere else entirely. When the extreme heat hit in early June, I thought she had quit laying. A couple of weeks later I found her new hidden nest with a dozen or so eggs in it!