https://www.mcmurrayhatchery.com/turkens_naked_necks.html
https://www.cacklehatchery.com/turkens-naked-necks.html
https://www.strombergschickens.com/product/Turken-Chicks/brown-egg-layers
If getting female is important to you.. I suggest ordering from a hatchery. That will also help to avoid bringing any unwanted disease into your flock as well... otherwise select an NPIP certified breeder. Chicks will risk males and older pullets maybe Marek's or other parasites and such that are possible to catch on pasture, anywhere. If I had no intention of breeding, I would order from hatchery even if it meant planning ahead for next season/year.
I like Turken a lot they were confident, interesting, and funny birds for the most part.
Good luck finding them!
ETA: did you know that you can get naked neck in many breeds now also... including Silkies?! They call the Silkies Showgirls..