Fence for fireplace screen.

Any Home Improvent stores sell picket fences

I'd get a pallet. Free from many stores.

Might be easier to just buy cheap 1x3s at a lumber store and build your own. That way you can build to suit height and length. Ready made fencing is often in standard sizes as far as height goes and may not suit your needs.

Craft stores, AC Moore or Michael's

While you could buy new, I'd check online forums, like Freecycle.org or Craigslist. If you don't see any offered in your area, just post that you are ISO (in search of) a piece of fencing.

Any of the big box home improvement store sell fence pickets and boards in the lumber department... just cut to the length you need, sand, prime and paint.

Most primitive/country decor stores have picket fences, but could or could not fit your fireplace. most primitive/country decor stores have picket fences, but could or could not fit your fireplace. Measure what size you need and you can go to big box hardware store and buy single wood privacy fence pickets and make your own. Click on the link below to get an idea.

https://www.hometalk.com/diy/outdoor/garden/flower-bed-picket-fence-recue-at-the-small-house-3807934

thanks to all who offered help. I really want reclaimed. I have this in my mind, hope to get it out!