Modern Ashkenazi Torahs are often (at least in part) written with turkey feathers. Not always - there are plenty of other quills that are acceptable (and reeds, plastic, and most say metal, among other options).
There are those who think that a Torah must be written with a feather from a kosher (species of?) bird (according to Wikipedia and more reliably, Keset ha-Sofer (Tinyana) 3:6 (English)). There are those who dispute the kashrut status of turkey.
Are there those who overlap in both of these sets such that they would dispute the kashrut of a Torah written with a turkey feather? If so, how is that handled practically? I assume if you buy a new Torah, you can commission the sofer to not use turkey feathers, but how does someone in this set ensure that his pre-existing Torah is kosher according to that set of opinions?
(This is not l'maaseh)