There are Crevecoeurs available, if you know where to look.
Livestock Conservancy Breeders List:
https://livestockconservancy.org/index.php/heritage/internal/breeders-directory
Jeannette Beranger's Crevecoeur Conservation page on Facebook:
https://m.facebook.com/CrevecoeurConservation
I don't Facebook, myself, but this page is viewable even without signing in.
Polish Poultry Breeders Club, also on Facebook:
https://m.facebook.com/polishbreedersclub
This club is for all crested birds, including Crevecoeurs and Sultans.
Last year's article in Backyard Poultry covered Jeannette's Crevecoeur project and gave names of several breeders:
https://backyardpoultry.iamcountrys...evecoeur-chicken-conserving-a-historic-breed/
I myself advertise on Poultry Show Central.
The best way I know of to find any breed in any state is to use the NPIP website:
http://poultryimprovement.org
Most serious breeders and people who show birds have their flock inspected and certified in the National Poultry Improvement Program yearly, so it's pretty much a current list.
But... it's a bit of a pain to use. First, you have to find the NPIP code for the breed you are looking for in the Stock Codes list under the "Animal Health" heading.
(Hint...large Crevecoeurs are "R88" and bantam Crevecoeurs are "W156".)
Then, you look for that code in the state you want to shop in. The full list of state reports is in the menu under "NPIP Participants by State/Territory."
(I am on page 5, in Missouri.) The hatcheries are on the list for their states, too.
Everyone on this list is inspected yearly, unless they have "H5/H7 AI Clean" in the additional classifications column, in which case they are inspected every six months. The inspection doesn't check for every possible disease, but you can have a good level of confidence that someone official has looked at the birds once or twice a year.
You will see contact info there, too, which should help. This is not an advertising list, so not all of them will necessarily have stock or hatching eggs for sale.
Hope this helps! Let me know if you have questions!