Sorry I missed your question and didn't respond earlier.
I really don't know. But it shouldn't be too difficult to buy a dozen of eggs if you ever go to the Netherlands or Belgium.
You can write to the ZOBK Speciaalclub in Belgium in English or translate your question with Google before sending : there is an adres and a contact form on their site. https://www.zobk.nl/clubrassen/doornikse-kriel
There is more info about de Tournaisis on this site too.
I doubt it that you can buy Tournaisis in the USA because someone told me its not permitted to import eggs or chickens from Europe. The breed is only recently expanding here.
I really don't know. But it shouldn't be too difficult to buy a dozen of eggs if you ever go to the Netherlands or Belgium.
You can write to the ZOBK Speciaalclub in Belgium in English or translate your question with Google before sending : there is an adres and a contact form on their site. https://www.zobk.nl/clubrassen/doornikse-kriel
There is more info about de Tournaisis on this site too.