Since turkeys are an American bird I find it hard to believe that
Meam Loez had a tradition that was not in ashkenazik tradition. The
sources I have looked at all say turkey is kosher because early generations
have eaten it. What happened in the first generation after turkeys were
discovered is not clear.
More fundamentally, it is not that simple. Ashkenazi Jewry does not eat
grasshoppers that Yemenite Jewry considers kosher. Though they can rely on
their traditions others cannot. Similar questions arise with respect to
Bison meat. Rav Tendler paskens (rules) that new animals found in Vietnam
are kosher as long as they have the kosher signs of split hooves and chew
their cud. He quotes a Chazon Ish that disagrees but states that he doesn't
understand the basis of the Chazon ish. A similar question arises in
wearing techelet ( blue dye) in tzizit ( 8 threads place on all 4 corners
of a garment. The scientific evidence that Murex Trunculus is the source
for techelet is overwhelming. The question is whether we rely on scientific
evidence to establish a tradition.