what happened? chickens laying outside of coop now...

[OHChick]

my chickens free range, my DH built them a really nice coop with nesting boxes which they have used consistently for a few weeks. i was down in the barn earlier and found a hen nested up on some hay and 2 eggs under her. i shooed her out of there and took the eggs away, but do i need to be worried that they somehow forgot their training? do i need to put golf balls back in the nest boxes? i don't want to be crawling all over the barn again and i'm confused why they'd stopped.

thanks in advance.

 

[Farmer Kitty]

Have they all stopped using the boxes or just the one? If one she might be broody. If all, has something changed in the coop? Different bedding, lighting, or something else?