They can be very sneaky about where they hide their eggs.
I'd confine them to coop and run for a week first(see below)....then maybe think about gloving up or adding calcium. An egg bound bird will usually appear to be very ill.
Not sure how prolific this 'breed', or rather cross, is at laying...she may be being affected by the shorter days....not all pullets lay thru the Dark Season.
Free range birds sometimes need to be 'trained'(or re-trained) to lay in the coop nests, especially new layers. Leaving them locked in the coop for a week or so can help 'home' them to lay in the coop nests. Fake eggs/golf balls in the nests can help 'show' them were to lay. They can be confined to coop and maybe run 24/7 for a few days to a week, provided you have adequate space and ventilation, or confine them at least until mid to late afternoon. You help them create a new habit and they will usually stick with it. ..at least for a good while, then repeat as necessary.