Hen stopped laying??

[nao57]

We just added on to the coop....I wonder if that freaked her out.

Yeah that would definitely have done something. I wouldn't be surprised if it will calm down once she adjusts.

With me, my chickens would lay on top of their coop, behind some boxes I'd put up there. One day I thought I could clean it up and get rid of the boxes and buckets...

Little did I realize that, the boxes and buckets were made it feel safe for them. So they stopped laying a few days. But then when I put the boxes and buckets back there they started laying there again.

 

[aart]

We did switch to layer feed

That could have an effect.....lower protein.

Is it possible she moved it somewhere else and we haven't found it?

Absolutely.
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.