my chickens aren't laying

[LTVK]

I have five hens, and four of them haven't layed all summer. They are free range, but I'm pretty sure they aren't hiding their eggs because when I shut them in the coop for a few days I still only get one egg a day. They are only a year and a half old, and they were laying fine all through the winter. I'm sure they get enough food, water, and ventilation.

 

[Ol Grey Mare]

Are they/have they been molting?

 

[LTVK]

Its possible. Thanks