Do they have an enlcosed building or similar enclosure to go into to sleep at night? All chickens that I have known of like to go into a darkened place to lay and that darkened place is usually where they sleep at night also. Realizing that it's not Winter where they might NEED shelter, but mine use it every night when they go to bed.
I do have older hens that are laying, however last year some of the pullets never did start laying until the following Spring but I'm pretty sure it's because they were polish divas LOL.
I also have some pullets and I'm waiting for them to lay. The oldest ones are now 12 weeks and no eggs yet (next younger ones are 10 weeks, then I have some that are about 8 weeks) so I am hoping to get eggs by Oct/Nov from the good layers and the polish divas may wait until Spring?
i made like a 12 by 12 (approx) chicken wire walled in area attached to my back porch. so the have a good outside cycle of light and dark. the back corner of the pen i have some nesting boxes and perches and i think they feel pretty safe in there. ive never actually seen them in the nesting boxes but they have been in there because they like to move the pine shavings all around